Global_Lab_Share

A Portfolio of Laboratory Science Experiments

 

 

 

 

The following is a collection of learning activities for students.  This was put together as a collaborative project from science educators from around the world.  They were asked to share their “favorite” laboratory experiments and the following document offers a diverse assortment of their science lessons.

 

 

 

Facilitator:

Bill Schoonover

science teacher

Vermont, USA

 

 

 

 

 

The following teachers participated in this project:

 

Mark Brereton, mbrereton@mlcsyd.nsw.edu.au, Sydney, Australia

Sharon Boardman, slboardman@adelphia.net, Rice High School, Vermont, USA

Jo Burke, Jo.Burke@stleonards.vic.edu.au, St Leonard's College, Melbourne, Australia

Vicki Cox, vcox@somerset.qld.edu.au, Somerset College, Gold Coast, Australia

Lis Haakonssen, Lis.Haakonssen@ed.act.edu.au, Copland College, Australia

Sue Kullerd, pepsaco1@aim.com,  Cedar School, Tortola, British Virgin Islands

Stewart Monckton, stewart.monckton@igs.vic.edu.au, Ivanhoe Grammar School, Victoria, Australia

Matthew R. Palubinskas, mpalubin@uvm.edu, UVM, Vermont, USA

Mark Poustie, mpoustie@plc.vic.edu.au, Presbyterian Ladies’ College, Melbourne, Australia

Chris Smyth, CSmyth@stpeters.sa.edu.au, St Peter’s College, Australia

Shelley Snyder, ssnyder@mtabe.k12.vt.us, Mt. Abraham Union High School, Vermont, USA

Phil Surks, phil@cvuhs.org, Champlain Valley Union High School, Vermont, USA

Kaye Venton, K.Venton@stpeters.qld.edu.au, St Peters Lutheran College, Queensland, Australia

 

 

 


TABLE OF CONTENTS

 

Lesson plan:                                                                                                 page

Using standard pH scales to Calculate Ka and Kb. 4

Properties of Ethanoic Acid. 6

Valence of Iron. 8

Iron Content in Steel. 9

Le Chatelier’s Principle. 15

Active Transport 17

Innate Behavior in Woodlice. 18

An Investigation of a Learned Response. 19

Chemical Digestion. 20

Rates of Photosynthesis. 22

Cell Division – Web Simulation. 24

Osmosis Practical 25

Cellular Respiration. 26

Asexual Reproduction – PowerPoint Exercise. 28

Bullseye!?. 30

Wavelength of laser light 31

The Great Hammer Challenge. 32

The great Stair Challenge! 33

Cool Dogs. 34

Egg Drop Project 35

Skittles Statistics - A Chi Square Analysis. 37

Egg Lab - diffusion. 41

Fortune Teller Fish. 43

Internet Map Project - Earth Science Lab. 44

Don’t skid out of control! 45

Running Smoothly. 46

Boy, is that hot! 47

Energy to Burn. 48

Interrelationships of Producers and Consumers. 49

Bouncing Popcorn. 53

Design your own experiment 54

Lab Report Format 55

Lab Report Format Practice. 56

Temperature of wax as it cools. 57

Measuring the Vitamin C content in a variety of fruit juices. 58

Temperature and Yeast Respiration. 61

Human Kidney Output 63

Movement of materials through cellular membranes. 66

Enzyme – Rate of Reaction. 67

Periodic Table Project 68

Rocket Activity. 70

Save the Egg! 72

Fluids Lab. 74

Newton’s Laws Worksheet 76

Fast Crystallization. 77

Planning an Experiment – Capillary Action. 79

Investigating a Drop of Liquid. 80

 

Factor affecting stream of liquid changing into droplets. 81

Using Hess' Law.. 82

A thermometric titration. 84

Planning an Experiment - CO2 in Carbonated Drinks. 87

Redox Titration with Potassium Permanganate. 88

The kinetics of the reaction between hydrogen peroxide and potassium iodide. 90

Surface Area to Volume Ratio Practical. 92

Factors Affecting Reaction Rates. 94

Titration Curves. 95

Optimum Conditions for Electroplating. 96

Buffers. 97

Electrolysis of Aqueous Electrolytes. 98

Analyze the Isotopes of Candium and Calculate Its Average Atomic Mass. 99

Predicting Chemical Reactions. 100

Measuring Mass and Counting Atoms. 105

Observing Light Emission From Wintergreen Mints. 106

Percent Sugar in Bubble Gum.. 107

Predator Prey Interaction. 108

Calculating Population Size. 110

Biological Community Balance. 112

 


Using standard pH scales to Calculate Ka and Kb.

Chemistry III: Investigation

 

 

NB: You are responsible for submitting work prior to due date, if you know you are going to be away on excursion or other activity. If sick on the due date you must call the school and leave a message for your teacher. Failure to fulfill the above commitments will result in late penalty of 5 %  per day , weekends included,  being applied.

 

 

Aim:

·        To determine [H+] of a weak acids and a weak base, using colour scales derived by adding indicators to acids and bases of known molarity.

 

·        To determine the Ka of weak acids and Kb  of weak base, using the [H +] established by help of the above colour scales.

 

Note on indicators:

Methyl orange and Orange lV change colour in the acidic range.

Indigo carmine and Thymol blue change colour in the basic range .

 

Method: You are to work in pairs ( a pair = 2 students) and divide the work so one student make up the acidic pH colour scales and the other make up the basic colour scales

 

PART 1.

Preparation of standard pH colour scales in acidic and basic range.

 

Acid Range:

Prepare two standard pH colour scales using HCl of different concentrations and adding one appropriate indicator to each of the scales.

Start with the 0.1 M HCL solution.

Carry out a range of dilutions which will give you solutions of different pH values.

A dilution of 1:10 will reduce the pH by 1

 

Basic Range:

Prepare two standard pH colour scales using NaOH of different concentrations and adding one appropriate indicator to each of the scales.

Start with 0.1 M NaOH

Carry out a range of dilutions which will give you solutions of different pH values.

A dilution of 1:10 will reduce the pH by 1.

 

PART 2:   

a) Determining the [H+] of the weak acid

1  Obtain 5ml of 0.1 M ethanoic acid

2  Divide the solution between 2 test tubes

3  Test with relevant indicators

4  Compare the colours with the standard pH colour scales and record the pH     

5 Repeat step 1-4 using the 1.0 M ethanoic acid                     

 

b) Determining the [H+]of the weak base

1  Obtain 5ml of 0.1 M CH3COONa

2  Divide the solution between 2 test tubes

3  Test with relevant indicators

4  Compare the colours with the standard pH colour scales and record the pH     

5  Repeat step 1-4 using the 1.0 M CH3COONa

 

 

PART 3:

Calculate the Ka and Kb for the weak acid and weak base respectively


Properties of Ethanoic Acid

Chemistry 2 Experiment

 

Due date: Monday 10. November

Value: 10 % of semester mark

Late Policy: Late submission will incur a penalty of 10% per day up to 50% .

         After 5 days the work will no longer be marked.

 

Aim: To prepare ethanoic acid from ethanol and compare its properties with those

         of ethanol.

 

Apparatus/materials:

 

Part A

Part B only

Bunsen burner & mat

Wooden splints

Tripod a gauze mat

Watch glass

Condenser with rubber tubing

pH paper

Boiling chips

Ethanol

Retort stand, boss head & clamp

Ethanoic acid

Round bottom flask

Magnesium ribbon

Take-of head

Marble chips

4 t-tubes

Sodium carbonate solution 2M

Beaker 100 cm3

 

Measuring cylinder 10cm3

Part C

Dropping pipette

Ethanol

Ethanol

 

Stopwatch

 

Potassium dichromate 3.5g

 

Concentrated sulphuric acid

 

Gloves

 

 

DANGER! !!! Conc. Sulfuric acid is very corrosive. Any acid spilt on skin should be

             washed off with running water.

             Acid MUST always be added to water because of the heat produced.

 

Method:

Part A.

1.      Use a measuring cylinder to pour 5 cm3 of water into the round bottom flask.

2.      Add 4 cm 3  conc. H2SO4 acid slowly with swirling of flask.

3.      Add app 3.5 g potassium dichromate (1V)  Swirl the flask to make a solution.

4.      Place a few boiling chips in flask

5.      Assemble apparatus as shown in diagram. Pass water through the condenser.

 

6.      Mix 2cm2 of ethanol with 6 cm3 of water. Add the mixture to the flask a little

at a time via the .

7.      Heat the flask and boil the contents for 15 minutes. This is called refluxing.

8.      After 15 minutes detach and reverse the condenser. Place the take-off head in the top of the flask to prevent vapour escaping.

9.      Heat the flask and collect 8cm3 of distillate

 

Part B.

1.      Divide the distillate into five parts

2.      Observe the colour and smell the distillate

3.      Dip a piece of pH paper into part of the distillate

4.      Add a small marble chip to part of the distillate

5.      Add 1cm3 of ethanol to part of the distillate.

Using a dropping pipette add three drops of conc. sulfuric acid.

Place the test-tube in a beaker of boiling water for three minutes.

Pour the content of test-tube into10 cm3 of sodium carbonate solution.

Note the smell

6.      Pour some ethanoic acid onto a watch glass.

Attempt to set fire to it with a lighted splint.

Part C:

Repeat step 1-4  and step 6 of Part B, but using ethanol

 

 

The report will be assessed on the following criteria:

Assessment Criteria

Excellent

Good

 

Adequate

Inadequate

Poor or not attempted

Data collecting:

·         Observing and collecting raw data

·         Presenting raw data

5

4

3

1

0

Data processing and presentation

·         Manipulating raw data

·         Presenting modified data

10

8

6

3

0

Evaluation & Conclusion:

·         Evaluating the results

·         Evaluating the procedure

·         Modifying the procedure

5

4

3

2

0

IB students

Complete   (3)

Partial    (2)

Not at all   (0)

Manipulative skills

·         Carrying out procedures with due regard to safety

·         Following a variety of instructions

 

 

 

Personal skills (a)

·         Working within a team

·         Recognizing the contributions of others

·         Encouraging the contributions of others

 

 

 

Personal skills (b)

·         Approaching investigation with motivation and perseverance

·         Approaching scientific investigation in an ethical manner

·         Paying due attention to environmental impact

 

 

 

 

Total marks  _____   /16

 


Valence of Iron

 

Aim:    to find a value for the valence of iron produced in a displacement reaction with copper.

 

Method:

·        Weigh an amount of steel wool around 3 gram.

·        Add this to a conical flask containing approximately 200 cm3 1.0M CuSO4 solution.

·        Swirl until the steel wool has disappeared completely.

·        Filter the mixture and wash any solids onto the filter paper.

·        Allow the paper to dry completely then weigh the paper.

·        Weigh 10 sheets of filter paper.

 

Analysis:

1.      Determine the average mass of a sheet of filter paper.

2.      Calculate the mass of copper precipitated from solution

3.      Calculate the number of moles of copper precipitated.

4.      Calculate the number of moles of iron used.

5.      Calculate the mole ratio of copper to iron in the reaction.

6.      Write the complete equation for the reaction.


Iron Content in Steel.

Chemistry 2: In Class Assessment Item/ Prac. Test.

 

Mark:                30

Weighting:        20% of Semester mark

Time allocated: Part 1 and preparation for task 2 is to be completed at home prior to first

                                  lesson allocated to the task.

                                  Part 2, to be completed in the following lesson and submitted

                                  Part  3 to be completed in the following double lesson and submitted

Assessment criteria:

Data collection and tabulation: Quantitative and Qualitative

Data processing

Conclusion

Evaluation of procedure and possible errors

Ability to work cooperatively

 

Aim:  To determine the iron content in a steel sample by titrating the Iron(II) ions with permanganate ions in acidic solution.

 

Part 1  (to be done prior to class experiment)

 

Background: Use half equations to write the equation for oxidation of Fe2+ ions with MnO4- ions.*

_____________________________________________________________________________

 

_____________________________________________________________________________

 

_____________________________________________________________________________

 

_________________________________________________________________________ /2

 

·          MnO4-  in acidic solution is reduced to Mn2+

At endpoint the solution will turn grey, rather than pink

KMnO4 can be standardised by titration with a standard solution of sodium oxalate, Na2C2O4

The oxalate, C2O42- ions will be oxidised to CO2

Using half equations write the equation for the redox reaction between C2O42- and MnO4-

 

___________________________________________________________________________________________________________________

 

___________________________________________________________________________________________________________________

 

___________________________________________________________________________________________________________________

 

___________________________________________________________________________________________________________________

 

______________________________________________________________________________________________________________ /2

 

Calculate the mass of Na2C2O4  required to make up 250 mL of a 0.05 M solution.

In the actual situation you will be given a known mass.

 

_____________________________________________________________________________

 

_____________________________________________________________________________

 

_____________________________________________________________________________

 

_____________________________________________________________________________

 

__________________________________________________________________________  /3

 

Part 2 (lesson 1)

 

Method:

Iron solution

1.      You will be given between 0.66 g and 0.74 g of steel.

2.      Add steel to a 100mL beaker.

3.      Add about 20 mL of 6 M H2SO4 solution

4.      Label and set aside while you standardise the provided KMnO4 solution.

 

Standardisation of KMnO4 solution

 

You will be given a pre weighed amount of sodium oxalate, which allows you to make up a standard solution of app 0,05M

1.      From the given mass of sodium oxalate make up 250 mL standard solution.

2.       Label and date.

3.      Standardise the provided KMnO4 solution by titration with 20.0 mL samples of the standardised Na2C2O4 solution.

 

The reaction between permanganate ions and oxalate ions in aqueous solution is slow, hence this titration is carried out at about 80C, at which temperature the reaction is rapid.

A permanganate solution acts as its own indicator in a titration. The reduction product, Mn2+ is colourless so the endpoint of the titration is indicated when the addition of a drop of permanganate solution causes the reaction to remain pink

4.      Using a pipette fill 20 mL  your of sodium oxalate, Na2C2O4 solution into  conical flask

5.      Add about 20 mL of diluted H2SO4

6.      Fill the burette with the provided KMnO4 solution

7.      Put a thermometer in the conical flask containing the Na2C2O4 solution. Heat the solution to about 80 C. Wash thermometer with a little distilled water before removing it

8.      Place conical flask  under the tip of the burette and a sheet  of white paper under the flask.

9.      Record the initial burette reading in your table

10.  While swirling the conical flask, run permanganate solution from the burette into the oxalate solution.

11.  Record the final burette reading in the table. Repeat titration at least three times

 

Data:  Prepare a table for your titration results and anything else, which needs to be

  Recorded. (Remember to attach when submitting)                                                     /3                                                               

 

 

Q 1  Why is sulfuric acid added to the conical flask?

 

_________________________________________________________________________ /1

 

 

Q 2  What is the purpose of the white paper under the conical flask?

 

________________________________________________________________________  /1

 

 

Q 4  Calculate the amount in moles of oxalate ions in 20mL of sodium oxalate solution

 

____________________________________________________________________________

 

____________________________________________________________________________

 

_________________________________________________________________________   /1

 

 

Q 5   Using the above reaction equation to calculate the amount of permanganate ions which

          will react with the oxalate ions in 20 mL of the sodium oxalate solution.

 

_____________________________________________________________________________

 

_____________________________________________________________________________

 

__________________________________________________________________________ /1

 

 

Q 6  What volume of the  permanganate solution contains this amount of permanganate ions?

 

___________________________________________________________________________/1

 

 

Q 7 Calculate the molar concentration of the potassium permanganate solution

 

____________________________________________________________________________

 

_____________________________________________________________________________

 

__________________________________________________________________________ /2

 

 

 

 

Part 3:  (lesson2-3)

 

Back to the Iron(II) solution:

 

1.      Transfer the solution to a 250 mL volumetric flask. ENSURE COMPLETE TRANSFER.

      and make the volume up to 250 mL.

2.      Transfer 20 mL of the iron solution to a conical flask and add about 20 mL of water.

3.      Titrate roughly with the standardised potassium permanganate solution to the first pink colour.

4.      Repeat the titration at least 3 times. Calculate the average volume of permanganate solution used.

 

 

 

Data:                                                                                                /3

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Data processing

 

Q1  Calculate the amount of iron ions formed when the total sample was dissolved.

(Treatment of errors not needed)                                                                                 

 

__________________________________________________________________________

 

__________________________________________________________________________

 

___________________________________________________________________________

 

____________________________________________________________________________

 

_________________________________________________________________________/4

 

 

Q 2  Calculate the amount (no of moles) of iron atoms in the sample and find the mass of iron in the sample.

 

_________________________________________________________________________/1

 

 

Q 3  Calculate the % of iron in the sample

 

____________________________________________________________________________

 

_________________________________________________________________________ /1

 

 

 

Q 4   Briefly evaluate the reliability of the analysis of iron content in steel.

        Uncertainties and effects

 

_____________________________________________________________________________

 

_____________________________________________________________________________

 

_____________________________________________________________________________

 

_____________________________________________________________________________

 

_____________________________________________________________________________

 

_____________________________________________________________________________

                                                                                   

                                                                  /4

 

 

 

 

Data:  part 2:

 

Steel wool:  Mass                      g

H2SO4:        Volume and concentration         mL   &       M

Observations of reaction:  smelly, bubbles , milky       

 

Na2C2O4: Mass        g

                 Volume       mL

                  Colour

 

Titration of KMnO4 with Na­2C2O4

Trial

Na­2C2O4 

     (mL)

2M H2SO4 in aliquot

          (mL)

    -   M    Na­2C2O4

                      ( mL)

Volume used

     (mL)

 

 

 

Burette initial

Burette final

 

 

 

 

 

 

 

 

Temperature of Na­2C2O4

Colour change

Absolute errors on measurements

 

 

Data Part 3:

 

Steel wool: Mass          g

                    Volume        mL

 

KMnO4:  concentration

 

 

Titration of Fe2+ sol, with KMnO4

Trial

Fe2+ solution

     (mL)

               KMnO4

                       (mL)

Volume used

Colour changes

 

 

Burette initial

Burette final

    (mL)

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Absolute errors

 

Part 3   ___/ 7

 

Part 2   ___/10

 

Part 3  ___/13

 

Total    ___/30


Le Chatelier’s Principle.

 

 

Aim:     To investigate what happens to the concentrations of product in a homologous equilibrium reaction, when the concentrations of one of the reactants, is changed.

The reaction to be considered is:

 

                        Fe3+ (aq)  +  SCN- (aq)   FeSCN 2+ (aq)

 

Method:

1          Record the colour of:    Fe3+ ions

                                                  SCNions

 

2          Using a measuring cylinder measure 25mL of 0.002M  KSCN in a beaker

Add 25mL distilled water

3                    Using a dropper pipette, add 5-6 drops of iron(III) nitrate solution to the

beaker and stir the solution.

4                    Record your observation

5                    Pour 5mL samples from the beaker into four Petri dishes, labelled 1 to 4 respectively. Place the dishes on a white surface.

6                    To dish 2 add 2-3 crystals of KSCN

7                    To dish 3 add three drops of iron(III)nitrate solution and stir.

8                    To dish 4 add a rice grain sized quantity of sodium fluoride and stir the solution

 

In your book record your raw data.

 

 

Now organize your raw data in a presentable fashion

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Analyse and evaluate your observations including the following points:

Independent variables, dependent variables and control

Cause of colour change

Equations for the relevant reactions

Uncertainties

 

_____________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________

 

 

 

Conclusion:

_________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________

 

 


 

BIOLOGY

Practical

 

Active Transport

 

INTRODUCTION

In most cases, movement of substances into and out of cells depends on the purely physical processes of diffusion and osmosis.  However, a cell can control the flow of substances across the cell membrane.  In some cases it can transfer a substance against a diffusion gradient.  This process is called active transport since it seems to be related to the activity of the cell.  It can be investigated in the manner described below.

 

MATERIALS

1.        100 ml conical flask

2.        Test tubes (5)

3.        Test tube rack

4.        50 ml measuring cylinder

5.        Filter funnel, stand and paper

6.        Active dry yeast (Tandaco)

7.        0.08M sodium carbonate solution.

8.        0.2% Neutral Red dye

9.        0.01M sodium hydroxide solution.

10.     0.01M ammonium hydroxide solution.

11.      Sucrose

12.    Dichloromethane

13.      Hot water

14.      Thermometer

15.      Bunsen burner

 

 

PROCEDURE

Mix hot and cold water to make about 50 ml of warm water (about 40° C).  Weigh out 1 g of dry active yeast and 1 g of sucrose and mix it into 25 ml of the warm water.  Measure 20 ml of sodium carbonate solution and add enough Neutral Red dye to produce a strong orange colour.  Sodium carbonate is alkaline.  What colour will the dye be in acidic solutions?

Add the sodium carbonate and dye to the yeast suspension and watch the mixture for a change in colour.  What could have caused the colour change?

Filter about 5 ml of the suspension into a test tube.  What colour is the filtrate?  What colour are the cells held on the filtrate paper?  How does this compare with the colour of the cells before the dye was added?  How does it compare with the colour of the sodium carbonate and dye?  If you add more dye to the filtrate, what colour do you get?  Is there sodium carbonate in the filtrate?  What happened to the dye which was added initially?

Put about 5 ml of the suspension into each of 4 test tubes.

(i)       To one add a few drops of sodium hydroxide solution.

(ii)      To the second add a few drops of ammonium hydroxide solution.

(iii)     To the third add 2 drops of dichloromethane and shake thoroughly.

(iv)     Heat the contents of the fourth gently to boiling.

Observe each test tube carefully and note any colour changes.

 

 

QUESTIONS   (optional)

(1)      What evidence do you have of the acidity inside the yeast cells?

(2)      What happens to the living yeast cells when they are boiled?

(3)      Why does the suspension change colour when it is boiled.

(4)      What does ammonia solution do to yeast cells?

(5)      What does dichloromethane do to yeast cells?

(6)      Are yeast cells damaged by alkaline solutions?

(7)      Propose a hypothesis to explain the difference in the response of yeast cells to ammonium and sodium hydroxides.

(8)      What evidence do you have that the movement of dye into yeast cells is an active process?

(9)      What does the word “active” imply about the process in the cells?

(10)   Suggest a test which you might apply to investigate this activity.


Innate Behavior in Woodlice

 

 

 

 

The students were shown how woodlice exhibit alternate behaviour (innate) when placed in a T maze (see diagram below).

 

They were asked to design, carry out and report on some factor that may affect innate behaviour shown by woodlice.

 

Note:    Alternate behaviour pattern would see a woodlouse turn left, right, left, right, etc, when placed in a T maze, such as the one below.

 

START

 
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 


 


An Investigation of a Learned Response

 

   Students were asked to work in pairs to investigate the effects of repeated attempts to complete the task (tracing the path using only the reflected mirror image for guidance). See the attached sheet and image.

 

They were to record results and discuss them, in the context of learning, in a practical report. DC, DPP, and CE are to be assessed.


(original practical which can be demonstrated to students)

 

Chemical Digestion

 

Introduction

Muscle layers contribute to the digestion of food by mechanically breaking down food into smaller particles and mixing the food with digestive juices.

 

The digestive juices contain digestive enzymes which bring about chemical digestion of food.  Digestive enzymes are extracellular enzymes released from gland cells.  Like all enzymes, digestive enzymes are specific in their requirements.

 

Amylase, an enzyme that digests carbohydrates, is produced by salivary gland cells and secreted into the mouth to convert starch into maltose.

 

Starch (polysaccharide) - - - - - - - - - - - -> maltose (disaccharide)

 

This is the first stage in the chemical digestion of starch to the simple monosaccharide, glucose.  Salivary amylase prefers a neutral to slightly alkaline pH and 37°C for optimum function.

 

(Optional Student Research): Investigate a factor that is likely to effect the ability of amylase to convert starch into maltose, making use of starch agar plates supplied.

 

Aim

1.      To compare the digestion of starch by using different concentrations of commercial amylase and to construct a graph of amylase activity.

2.      To show that saliva contains amylase and estimate the activity of salivary amylase by using the graph. (optional)

 

Hypothesis

Propose an hypothesis for this experiment.

 

If   __________________________________________________________________

_______________________________________________________________________________________________________________________

 

then    ______________________________________________________________

_____________________________________________________________________

__________________________________________________

 

Requirements:     

2 petri dishes containing starch agar with 3 pre-cut wells

% amylase solutions (dist water, 0.1, 1, 3 and 5%)

Labels

Trays for Petri Dishes

Large Test tube

Teat pipettes

Dilute iodine

Distilled water

Access to incubator set at 35°C

 

 

Method:                   1. Collect the container with your equipment.

2. Label the base of your 2 petri dishes with your name and label each perimeter well with the % concentration of amylase (0, 0.1, 1, 3, 5 or unknown)

3. Into the large test tube, collect your own saliva to a depth of 1 cm.

4. Using a different teat pipette each time, fill the wells with the appropriate amylase solution or saliva. DO NOT LET THE WELLS OVERFLOW.

5. Carefully tape the lid onto each petri dish, taking care not to cause any solutions to spill from their wells.

6. Put the dishes into the incubator overnight.

 

NEXT DAY

 

Remove lids from the petri dishes and pour enough dilute iodine solution over the starch agar to cover it. Swirl gently for 1 minute, pour off the iodine and leave the dishes overnight.

 

NEXT DAY

 

Inspect the plates and measure the diameter of the clear circles around each well.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Rates of Photosynthesis

 

  Photosynthesis is the process in which light energy is converted to the chemical energy of sugars. It can be summarised in the following equation.

 

        Carbon Dioxide  +  Water                                                Glucose  +  Oxygen

                                                       Light & chlorophyll

 

 

  This process occurs in the chloroplasts of plant cells that are primarily found in the leaves. To measure the rate of photosynthesis, the time it takes for leaf discs to rise to the surface of water in a beaker, can be measured.

   When discs are cut from fresh leaves and kept moist, the cells of the leaf remain alive and are capable of carrying out photosynthesis. Normally these leaves would float in water, but if the air is removed from the spongy mesophyll air spaces by placing the leaves under low pressure, they will sink because they become less buoyant.

   In the presence of light, the cells in the leaf photosynthesise and release oxygen which makes them more buoyant until eventually they float to the surface. The quicker the discs rise, the faster the rate of photosynthesis has occurred.

 

An Investigation of factors affecting the rate of Photosynthesis

 

   You will be shown a demonstration of a method to measure the rate of photosynthesis in ivy leaf discs. You will use this basic method to design an investigation into the effects of one factor on the rate of photosynthesis in ivy leaves.

 

Time allowed: 2 hours.              Pl a) and b) assessed.

 

You may consult with Mr. Harris (lab tech) or myself as to what equipment is available for this investigation.

 

 

If your planning is suitable you will then run the investigation. If not, a basic outline will be provided for you to investigate one factor affecting photosynthesis.

Time allowed: 2 hours.              DC, DPP and C&E assessed.

 

 

CGSmyth

 

 

 

 

 

 

 

 



                                                RATE OF PHOTOSYNTHESIS

 

 

PART A   VALIDATING THE TECHNIQUE

 

Aim

To demonstrate the leaf disk method as a way to investigate the rate of photosynthesis.

 

Materials Required

Fresh green leaves (eg: Ivy)

Cork borer or hole punch (approximately 8 mm)

Buchner flask and Vacuum pump or a 50 mL plastic syringe

 

Overhead projector                                        1 x 25 mL Beakers

Sieve                                                                Forceps

50 mL measuring cylinder                            Distilled water

Stop watch                                                      6% sodium bicarbonate solution

 

Method

1.      Cut 10 small (5-10 mm) leaf discs using the cork borer or hole punch provided and transfer these immediately to a 100 mL beaker containing distilled water.

2.      Transfer the discs to the Buchner flask which is approximately half full with distilled water.  Place a rubber stopper into the flask and operate the pump for approximately 5 minutes to remove the air from the discs.  If the pump is working correctly bubbles should appear in the water.  Remove the rubber stopper and turn off the water.  The discs should sink.  If an insufficient number do so, then more time in the flask extracting their air will be required.

         OR

3.      Transfer the discs to approximately 20 mL of distilled water in a 50 mL syringe, and expel the air.  Now place a large rubber stopper over the small hole in the tip of the syringe and slowly pull the plunger out.  Notice that the air which was dissolved in the water and the air from inside the leaf form small bubbles, which then join to form a large bubble.  This air may then be expelled as before and the process repeated until the discs sink to the bottom, as in part (a).

4.      Pour the water containing the discs through the sieve and then transfer 10 discs into a beaker containing 50 mL sodium bicarbonate solution, on the overhead projector (OHP).

5.      Turn on the OHP and immediately start the stopwatch.  Record the  time in seconds for each disc to rise.  (This should be somewhere between 4 and 15 minutes).  Take note of any discs that do not fit the pattern of the others in the beaker for the time taken to rise.

6.      Work out the average time taken (in seconds) for the discs to rise in each beaker.  To estimate the rate of photosynthesis, calculate the reciprocal of the average time and then convert to scientific notation.

 

Example

Average time taken for the discs to rise              =       3 minutes 40 seconds

                                                                              =       220 seconds

Estimate of the rate of photosynthesis                =       1/220

                                                                              =       0.0045 sec-1

In scientific notation                                            =       4.5 x 10 -3 sec-1


Ivanhoe Grammar School: VCE Biology Unit 1.

 

Cell Division – Web Simulation

 

Aim:  Increased Understanding of the Process of Mitosis.

 

Background: 

 

During the process of mitosis the nucleus passes through a number of stages that result in the formation of identical nuclei.  If you look at a sample of tissue where large numbers of cells are undergoing mitosis you can attempt to estimate how long the nucleus spends in each phase of the cell cycle.

 

The observation of the root tips of onions (as in the last practical) can be used to estimate the how long the (as a %) of time the cell spends in Interphase, prophase, metaphase, anaphase and telophase. If you take a sample of cells that are all passing through the cell cycle and 10% are in a certain phase of the cell cycle, you can assume that the cell spends 10% of its time in that phase.  (Remember that this % would only apply to the tissue under investigation).

 

NOTE:

 

In this practical you will be observing plant cells.  There are some important differences between mitosis in plant and animal cells. These differences can be summarised as follows:

 

  1. Centrioles are not present in plant cells.
  2. A cell plate forms between the two cells at the end of telophase – this is the beginning of the new well wall.

 

 Method:

 

 

  1. go to this web site
  2. work through the first pages until you come to a table that looks like the one below.

 

 

 

 

 

 

Interphase

Prophase

Metaphase

Anaphase

Telophase

Total Number of cells

 

Number of cells

 

 

 

 

 

 

 

 

 

 

    36

 

% of total

 

 

 

 

 

 

 

 

  100%

 

 

  1. Click onto the next page. You will be shown a cell. Click on the stage of mitosis that the cell is in.  Once you have correctly identified the stage, add it to the table above.  When you complete all 36 cells, fill in the table above.

 

  1. Use the data you have collected to calculate the % of time the cell spends in each stage.

 

  1. List the stages of Mitosis in the space below and describe what is happening to the chromosomes – also include Interphase in this list, but limit description of activity to the events that are relevant to mitosis.

Ivanhoe Grammar School : IB Biology .

 

Osmosis Practical

 

Introduction.

All living things consist of cells or their products and all cells are surrounded by a cell membrane.  Thus all the materials that originate in the external environment, but are required inside the cell must pass through the cell membrane.  These materials include a range of dissolved salts, minerals sugars and gases.  Cell membranes are not permeable to all substances – in other words they are semi – permeable. 

 

Many materials move through the cell membrane by diffusion – from high concentrations to low concentrations.  Substances that are not able to move in this fashion must be “pumped” though the cell membrane by active transport at the cost of some energy use by the cell.

 

 

Water is one of the most abundant and important substances within a cell.  The movement of water across a semi-permeable membrane from an area of low solute concentration to an area of high solute concentration is called osmosis.

 

An egg is a large cell containing mainly water, proteins and salts that are required for the growing embryo.  Bird eggs are surrounded by a hard shell, inside of which is the cell membrane.  This provides an excellent model for understanding the function of the cell membrane.

 

If birds eggs are left in dilute hydrochloric acid over night the shell will dissolve away, leaving the membrane exposed.

 

Materials:

 

1 Hen’s egg – which shell removed by acid.

10% and 5% NaCl Solution

Distilled Water

Accurate balance.

Spoon

 

Method:

 

  1. Remove egg from acid – rinse under tap water – gently dry – and record mass in a data table.  (NB do not attempt to remove any fragments of shell that remain attached to the egg)
  2. Place the egg in 5% NaCl solution and leave for 10 minutes – ensure that the egg is fully covered.
  3. Remove – dry and reweigh the egg.  Record any other observations
  4. Place the egg in 10% NaCl solution for 10 minutes – ensure the egg is fully covered.
  5. Remove, dry and reweigh the egg.  Record any other observations.
  6. Place the egg in the distilled water and leave for 10 minutes – ensure that the egg is fully covered.
  7. Remove, dry and reweigh the egg. Record any other observations.
  8. Collect class data to allow calculation of averages.

 

Calculate the change in mass for the egg in the 3 solutions.  You can assume that the mass on being placed in the second solution was the same as it was when it left the first – and so on.

 

 

This practical should be written up as a full practical report using the guidelines provided.


Ivanhoe Grammar School : IB Biology .

 

Cellular Respiration

 

Introduction.

 

The amount of energy liberated from a food source during cellular respiration can be modelled by releasing the energy from the same food source as heat, using this heat energy to heat water and through a simple formula calculating the amount of energy released.  This can be achieved because it is known that the energy required to raise 10ml of water through 1OC is 42 J.  Thus is 10 ml of water is raised by 10OC the amount of energy required used was 420 J.

 

 

 

 

NB: Use 20 mL of water in the test tube – not 10 mL as indicated to prevent the water from boiling (hopefully!).

 

 

Complete the practical as directed above and then repeat for a different type of nut – a full practical write up of this activity will be required. You should exchange data with as many other groups as possible to allow average figures to be calculated. It is important that you calculate the amount of energy per gram for each of the types of nut used – not just the amount of energy released.


 

Click here to access an Excel document to run the Peanut Calculator

 

Amount of water

Units of water

Start Temp

Final Temp

Temp Change

Energy Released

Mass of Peanut

Energy Per g (J)

Energy Kj per g

 

Peanut

 

21

2.1

22

50

28

2470

0.7

3528

 

24

2.4

21

48

27

2722

0.5

5443.2

 

23

2.25

20

45

25

2363

0.5

4725

 

24

2.4

18

39

21

2117

0.7

3024

 

 

 

Test Tube Average

4180.05

4.18005

21

2.1

22

54

32

2822

0.5

5644.8

 

24

2.35

21

56

35

3455

0.6

5757.5

 

 

 

Flask Average

5701.15

5.70115

Cashew

 

 

 

 

 

 

 

 

 

 

22

2.15

21

37

16

1445

0.3

4816

 

21

2.1

22

43

21

1852

0.7

2646

 

22

2.2

17.3

41

24

2171

0.8

2714.25

 

24

2.4

21.3

30

9

877

0.6

1461.6

 

 

 

Test Tube Average

2909.46

2.909463

22

2.2

20

63

43

3927

0.8

4908.75

 

23

2.25

21

55

34

3213

0.6

5355

 

21

2.1

21.5

64

43

3749

1

3748.5

 

 

 

Flask Average

4670.75

4.67075

Macadamia

 

22

2.2

21.3

42

21

1913

0.5

3825.36

 

22

2.15

21

57

36

3251

0.5

6501.6

 

22

2.2

19

46

27

2495

0.8

3118.5

 

22

2.2

22.5

90

68

6237

1.5

4158

 

 

 

Test Tube Average

4400.87

4.400865

23

2.3

20

73

53

5139

0.7

7341.6

 

21

2.1

18

59

41

3616

0.7

5166

 

 

 

Flask Average

6253.8

6.2538

 

 


Ivanhoe Grammar School : VCE Biology. Unit 2.

 

Asexual Reproduction – PowerPoint Exercise.

 

Stage 1

 

Reorder the following paragraphs into their correct sequence. (You can highlight and then drag and drop the paragraphs)

 

Later Prophase. Later in prophase, the chromosomes have become still more distinct, and the nucleolus has disappeared. The nuclear membrane also disintegrates during prophase.

 

Metaphase. At metaphase, the chromosomes line up along an imaginary line running through the equator of the call. The nuclear membrane has disappeared by this stage

 

Interphase. The large nucleus with its darkly-stained nucleolus is clearly visible in this inter-phase cell. The chromosomes, too long and thin to be visible as discrete, rod-like bodies at this stage, undergo replication during interphase.

 

Onion Roots Each root on this onion bulb has a region of rapid call division, the apical meristem, just behind the root cap. When the root is killed, fixed, and stained, it provides excellent material for studying mitotic cell division.

 

Prophase. In this early prophase slide, the chromosomes have begun to coil and condense, appearing as a mass of dark, tangled threads. Although it is not apparent at this magnification, each chromosome is already two-stranded at this stage.

 

Anaphase. During anaphase, the centromeres divide and the two chromatids of each double-stranded chromosome move apart toward opposite poles of the cell. The cell temporarily has twice its usual chromosome number.

 

Sectioned Root Tip. This median longitudinal section through an entire root tip shows a well-defined root cap of protective, non-dividing calls at the extreme right. Many meristematic cells in various stages of mitosis may be recognized by their darkly-stained chromosomes.

 

Telophase. The chromosomes have reached the two ends of the cell. Traces of the spindle are still apparent in this photograph.

 

Metaphase. This slide clearly shows the spindle fibres running between the poles of the cell. At metaphase, the centromeres of each chromosome attach to a spindle fibre. Because this is a plant cell, there are no centrioles at the poles of the spindle.

Later Telophase. During telophase, cytokinesis (the division at the cytoplasm) begins. This photograph clearly shows the cell plate beginning to form in the centre of this plant cell. Cell plate formation proceeds from the inside outward.

 

Daughter Cells Telophase ends when the nuclear membranes and nucleoli have been reassembled, and the chromosomes have uncoiled and become diffuse once again. In this slide, the completion of cytokinesis has produced two new cells whose nuclei are just entering interphase. Each new nucleus has the same number and kind of chromosomes as the parent call had. The cell cycle is complete.

 

Later Anaphase. In this slide, the new, single-stranded chromosomes have almost arrived at opposite ends of the cell. The mechanism of chromosome movement is not entirely understood. The spindle fibres apparently play a role in drawing the chromosomes apart.

 

 

Stage 2. 

 

Open the power point Presentation called “Mitosis Activity” and view the slides.  They are in the incorrect order.  Use the slide sorter view to sort them out into the correct order.

 

 

Stage 3. 

 

Paste the paragraphs from Stage 1 onto (into?) the correct slides from Stage 2 and you should have an account of mitosis.

 

 

 


Physics/Mechanics                                                                                            CVUHS

Phil Surks                                                                                                        Room 174

 

Bullseye!?

Use your expert knowledge of projectile motion to hit the center of the target.  You can use whatever means you wish to characterize the motion of the ball as it rolls down the ramp and across the table, but your ball may only leave the surface of the table one time. 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 


 

Wavelength of laser light

 

This lab will use the laser and a diffraction grating to create a pattern of antinodes on a wall.  By making measurements, determine the wavelength of light generated by the laser.  (See Diagram below)

 

 

Use a diffraction grating, which has a spacing of roughly 50 lines per millimeter (note the value of your grating).

The expected wavelength of light generated by the Helium-Neon laser is 6328 Å, or 6.328 x 10 -7 m or 632.8 nm. (This may vary from laser to laser.)

         

Writeup:  Minilab including title, date, partners, hypothesis, data in a table, sample calculations, % discrepancy error, and a conclusion comparing discrepancy and relative error.

 


Phil Surks                                                                                      Room 160

Physics/Waves                                                                               CVUHS

 

The Great Hammer Challenge

How Much Work is Done to Drive a Nail
into a Piece of Wood?

 

 

Ever wondered?  Now you have an opportunity to find out using the PVC tube and the 1 kilogram mass before you.  By dropping the mass through the tube and onto the nail, and employing what you know about work and energy transformations determine how much energy is transferred to the nail as it is driven through the board.  Be sure to outline your strategy and show your relevant equations and computation.

 

Using your value of the work required to pound the nail, please answer the following questions.

1.   Assuming it takes 5 strokes of a hammer to get the same nail into the same board, what is the kinetic energy of each stroke?

 

2.  If the hammer head has a mass of .5 kg, what would the velocity of a hammer be as it strikes the nail?

 

3.  If the nail is 3” (8 cm) long, what is the force delivered to the nail on each strike of the hammer?

 

4.  If a pneumatic nail gun drives the nail into the board in one shot (and buries the head), what force does the nail gun exert on the nail?

 

 


Phil Surks                                                                                      Room 174

Physics/Waves                                                                               CVUHS

 

The great Stair Challenge!

Can you do more work per second than a horse??

 

 

Pretty odd question eh?  Some people can, but only for a short time.  Let’s see how you measure up to a horse’s rate of doing work.  (By the way, this is the origin of the term “horsepower”.)  To do this, we will see how fast we can (SAFELY) run up from the 1st floor of CVU to the 2nd.  However, first you must prepare your equation to determine your work rate.  What are the major factors you must consider?  (Note, you can ignore friction and air resistance.)  After you have analyzed the situation, I will give each team a stopwatch and a meter stick.  Good luck, BE CAREFUL, and have fun!

 

Some constants and relations you may need:

g=9.8 m/s2

1 Watt=1 Joule/second

1 HP=746W

1 kg weighs 2.2 lbs

1 hour=3600 seconds

 

  • Determine the work done by each member of your team in getting up the stairs.
  • Determine the power developed (in Watts and kW) by each member of your team in getting up the stairs.
  • Compare the most powerful and least powerful members of your team by calculating the percent difference.
  • Calculate the kiloWatt-hours of energy used by each member of your team.
  • Using these values, for how long could each member of your team power a 60-Watt light bulb?

 

Your write-up should include sample calculations and conclusions.  Be sure to answer all of the questions.  There is no need for an equipment list. 


                            

 

Cool Dogs

The purpose of this tasty little experiment is to see how different types of hot dogs (yum!) will cool differently and hypothesize why this occurs based on their ingredients and nutritional information.  By measuring the rate that a warmed hot dog cools, we will observe, measure, and explain the capacity of different types of hot dogs to retain heat.

 

To do this, we will first obtain two or three different types of hot dogs. Then cut off the ends of the hot dogs, and measure their mass so that the masses of the hot dogs are the same. Connect your Temperature Probe, start Logger Pro, and use the default settings. Place one hot dog on a paper plate and heat it in a microwave oven for 15 seconds on the highest setting. Insert a Temperature Probe halfway into the hot dog (lengthwise), and start collecting temperature data. Collect data for 3 minutes. Store each trial so that you can plot or analyze all of the data at the end of the experiment. Repeat this process for the other hot dogs.

For best results, make sure that

·     The hot dogs are the same mass.

·     The hot dogs are heated for the same amount of time.

·     The Temperature Probe is inserted into each hot dog identically.

·     The temperature data are collected for the same total amount of time.

 

Data Analysis:

Select a 30 second span of time near the beginning of each data set, and calculate the best-fit line equation. The slope of the line will be considered the rate of cooling for a given hot dog sample. Examine the labels of the packages of the hot dogs. Record the nutrition data for each type of hot dog, paying particular attention to the items that differentiate the products from each other.


Egg Drop Project

 

 

            Your team will design and construct a device that will allow you to drop a raw egg from a height of approximately 5.0m onto a concrete pad without breaking the egg.  You may not have any contact with the device or egg after the moment of release.  Your construction material will consist of no more than 100 plastic straws and no more than 1.0m of masking tape.  The entire meter of tape will be given to you when you request it.    A grade A large egg (diameter » 4 cm, length » 5.5 cm, mass 55-60g) will be given to you on the drop day.  You are expected to be aware of and to use principles of physics in the design.  You may use normal tools such as scissors. 

 

 

The scoring will be as follows:

 

20 points

Completion of the project in the specified amount of time.  (4 class periods with no design or construction taking place outside of class)

 

50 points

Part I: Write an engineering and design report of 2-3 pages which clearly describes the principles of physics used to allow the egg to survive the drop.  The report must consist of three parts: (1)  analysis of the reasons an unprotected egg will break (use physics), (2) a description of your device (a picture will help), and (3) a description of how the laws of physics apply to your device and allow it to deliver your egg unscathed. As a minimum, the discussion must include the application of Newton's Laws and concepts of momentum.

 

Part II: Make a 3-5 minute oral presentation in which you show your device and explain how your device takes advantage of the laws of physics to allow your egg to survive the fall intact.

 

20 points

Cooperation as a team which includes positive interaction and feed-back, equal sharing of tasks and ideas, and shared dedication to the project.

 

Bonuses

5 points for early completion (construction completed w/ 35 minutes remaining in last class)

1 point for every 5 straws returned in mint condition

10 points for aesthetic design

 

Penalties

5 points for cracked egg

10 points for smashed egg

40 points for exceeding material limits


Teacher’s notes:

We did this lab in Physics. You could also use it in Physical Science.

 

We dropped from the top of the bleachers in the gym. You could use other high drops: from a window, from the bleachers in the football stadium, from a cherry picker, etc.

 

Make available for each group:

a square yard of tightly woven nylon material

a paper lunch bag

a plastic shopping bag

2 - 3 balloons

two paper clips

five feet of string

three 8 1/2 x 11 inch sheets of paper

masking tape

a raw egg (now you know it’s going to be fun!) or a light bulb

 

Materials (For the entire group)

a scale sensitive to ounces (e.g. postal scale)

 

See also: http://mars.jpl.nasa.gov/classroom/pdfs/MSIP-MarsActivities.pdf page 130

 

 


AP Biology Lab               Name                        

 

Period _____                      Date              

 

Skittles Statistics - A Chi Square Analysis

Have you ever wondered why the package of Skittles you just bought never seems to have enough of your favorite color?  Or, why is it that you always seem to get the package of mostly orange Skittles?  What’s going on at the Mars Company?  Is the number of the different colors of Skittles in a package really different from one package to the next, or does the Mars Company do something to insure that each package gets the correct number of each color of Skittles? Here is a recent email I received from the company
        In response to your email regarding SKITTLES BITE SIZE CANDIES.
        Thank you for your email. 
        The flavor blend is 20% of each flavor. 
        Have a great day! 
        Your Friends at Masterfoods USA 
        A Division of Mars, Incorporated 
 

One way that we could determine if the Mars Co. is true to its word is to sample a package of Skittles and do a type of statistical test known as a “goodness of fit” test.  This type of statistical test allow us to determine if any differences between our observed measurements (counts of colors from our Skittles sample) and our expected (what the Mars Co. claims) are simply due to chance or some other reason (i.e. the Mars company’s sorters aren’t doing a very good job of putting the correct number of Skittles in each package).  The goodness of fit test we will be using is called a Chi Square (X2) Analysis. 

We will be calculating a statistical value and using a table to determine the probability that any difference between observed data and expected data is due to chance alone.

 

We begin by stating the null hypothesis. A null hypothesis is the prediction that something is not present, that a treatment will have no effect, or that there is no difference between treatment and control. Another way of saying this is the hypothesis that an observed pattern of data and an expected pattern are effectively the same, differing only by chance, not because they are truly different.

 

What is our null hypothesis for this experiment? ________________________________

 

_______________________________________________________________________ 

 

_______________________________________________________________________

 


To test this hypothesis we will need to calculate the X2 statistic, which is calculated in the following way:

X2 = Sum of (o-e)2

                    e

            where o is the observed (actual count) and e is the expected number for each color category. The main thing to note about this formula is that, when all else is equal, the value of X2 increases as the difference between the observed and expected values increase.

 

Procedure

Wash your hands and your work area, you will be handling food that you may want to munch on later.

  1. Lay out a large sheet of paper—you’ll be sorting Skittles on this.
  2. Open up a bag of Skittles and split them between the members of lab group.
  3. DO NOT EAT ANY OF THE SKITTLES (for now!)
  4. Separate the Skittles into color categories and count the number of each color of Skittles you have. 
  5. Record your counts in Data Chart 1.
  6. Determine the Chi square value for your data.

 

 

Data Chart 1

 

Yellow

Red

Orange

Green

Purple

Total

 

Observed

(o)

 

 

 

 

 

 

 

Expected (e)

 

 

 

 

 

 

 

Difference

(o-e)

 

 

 

 

 

 

 

Difference

Squared (o-e)2

 

 

 

 

 

 

 

(o-e)2/e

 

 

 

 

 

 

 

 

Σ (d2/e) =

X2

 

 

 

 

 

 

 

 

 

Now you must determine the probability that the difference between the observed and expected values occurred simply by chance.  The procedure is to compare the calculated value of the chi-square to the appropriate value in the table below.  First examine the table.  Note the term “degrees of freedom”.  For this statistical test the degrees of freedom equal the number of classes (i.e. color categories) minus one:

degrees of freedom = number of categories –1

 

In your Skittles experiment, what is the number of degrees of freedom? ___________

 

The reason why it is important to consider degrees of freedom is that the value of the chi-square statistic is calculated as the sum of the squared deviations for all classes. The natural increase in the value of chi-square with an increase in classes must be taken into account.

 

Scan across the row corresponding to your degrees of freedom.  Values of the chi-square are given for several different probabilities, ranging from 0.90 on the left to 0.01 on the right.  Note that the chi-square increases as the probability decreases. If your exact chi-square value is not listed in the table, then estimate the probability.

 

 

                                    Accept the null hypothesis                                 Reject

 


Degrees of

Freedom

Probability

0.90

0.50

0.25

0.10

0.05

0.01

1

0.016

0.46

1.32

2.71

3.84

6.64

2

.0.21

1.39

2.77

4.61

5.99

9.21

3

0.58

2.37

4.11

6.25

7.82

11.35

4

1.06

3.36

5.39

7.78

9.49

13.28

5

1.61

4.35

6.63

9.24

11.07

15.09

 

Notice that a chi-square value as large as 1.61 would be expected by chance in 90% of the cases, whereas one as large as 15.09 would only be expected by chance in 1% of the cases. Stated another way, it is more likely that you’ll get a little deviation from the expected (thus a lower Chi-Square value) than a large deviation from the expected. The column that we need to concern ourselves with is the one under “0.05”.  Scientists, in general, are willing to say that if their probability of getting the observed deviation from the expected results by chance is greater than 0.05 (5%), then we can accept the null hypothesis.  In other words, there is really no difference in actual ratios…any differences we see between what Mars claims and what is actually in a bag of Skittles just happened by chance sampling error.  Five percent!  That is not much, but it’s good enough for a scientist.

 

If however, the probability of getting the observed deviation from the expected results by chance is less than 0.05 (5%) then we should reject the null hypothesis.  In other words, for our study, there is a significant difference in Skittles color ratios between actual store-bought bags of Skittles and what the Mars Co. claims are the actual ratios.  Stated another way…any differences we see between what Mars claims and what is actually in a bag of Skittles did not just happen by chance sampling error.


Analysis

1. Based on your individual sample, should you accept or reject the null hypothesis?       Why?

 

 

 

2. If you rejected your null hypothesis, what might be some explanations for your           outcome?

 

 

-----------------------------------------------------------------------------------------------------------

Now that you completed this chi-square test for your data, let’s do it for the entire class, as if we had one huge bag of Skittles. Using the information reported on the chalkboard, complete Data Chart 2.

Data Chart 2

 

Yellow

Pink

Orange

Green

Purple

Total

 

Observed

 

 

 

 

 

 

 

 

Expected (e)

 

 

 

 

 

 

 

Deviation

(difference between expected and observed)

 

 

 

 

 

 

 

Deviation

Squared (d2)

 

 

 

 

 

 

 

d2/e

 

 

 

 

 

 

 

 

Σ (d2/e) =

X2

 

 

 

 

 

 

 

 

Conclusions
Based on the class data, should you accept or reject the null hypothesis?  Why ?

 

 

 

 

What is the purpose of collecting data from the entire group?



Biology Lab                                                                Name                                                             

 

Date                                                                            Period            

 

Egg Lab - diffusion

 

Objectives

            Explain the changes that occur in a cell as a result of diffusion

            Distinguish between hypertonic and hypotonic solutions

 

Materials (per group of 3 or 4)

            2 Baggies                    permanent marker                 400 mL of vinegar

            balance                       plastic container                     distilled water (day 2)

            2 fresh eggs                paper towels                           corn syrup (day 2)

 

Purpose

            In this lab, you will use eggs with a dissolved shell as a model for a living cell. You will then predict the results of an experiment that involves the movement of water through a membrane.

 

Procedure

Day 1

1. Label one baggie Egg 1 and the other baggie Egg 2: syrup. Also put the initials of the people in your

            group on the baggies.

2. Measure the mass of each of the two eggs to the nearest .01g. Put the information in the data table.

            Caution: When handling raw eggs, clean up any material from broken eggs immediately. Wash your hands with soap and water after handling the eggs.

 

3. Place an egg in each baggie. Pour 200 mL of vinegar into each baggie. Adjust the baggie in the

            plastic container, so that the egg is immersed in the vinegar. Do not seal the baggie. Put the

            plastic container in a place indicated by your teacher.

4. Clean up your work area and wash your hands before leaving the lab.

 

Day 2

5. After returning to the lab, observe your eggs. Record your observations in the data table

6. Pour the vinegar from the baggie into the sink. Rinse the eggs with water and gently place them on a

            paper towel to dry. Do not mix up your eggs!

7. Mass each egg, and record the measurement in the Table 1.

8. Return Egg 1 to its baggie and cover the egg with water. Return Egg 2 to its baggie, and cover

            with corn syrup solution provided by your teacher. Return eggs to the same place as before.

9. Clean up your work area and wash your hands before leaving the lab.

Prediction

            Predict how you think the mass of each egg will change after 24 hours in each liquid.

 

                                                                                                                                                           

 

                                                                                                                                                           

 


 

Data Table

Egg 1

Egg 2 (syrup)

Day 1 - Initial Mass of Egg

 

 

Day 2 - Mass of Each Egg

 

 

Day 3 - Final Mass of Each Egg

 

 

 

 

Day 3

10. Observe your eggs after 24 hours. Record your observations in the Table 2. Measure and record

            the final masses of the two eggs.

11. Dispose of your materials according to the directions from your teacher.

12. Clean up your work area and wash your hands before leaving the lab.

 

 

 

 

Analysis

13. What effect did the vinegar have on the eggs?

 

 

 

 

14. How did your results compare with your prediction?

 

 

 

 

15.  What caused the change of appearance in Egg 1 after it soaked in water?

 

 

 

 

16. What material seems to have moved through the membrane of Egg 2 after it soaked in the syrup?

 

           

            In what direction did it move?

 

 

 

17. Which egg was in a hypertonic solution?                                         

 

                                    a hypotonic solution?                                       

 

 

Teacher’s notes: dilute the corn syrup 3 parts water to 1 part corn syrup.

 

Have extra eggs on hand (that you have massed) because some groups will break their eggs.


AP Biology Lab                                                Name                                                              

 

Date                                                                 Period             

 

Fortune Teller Fish

 

Introduction

            When placed in the palm of your hand the miracle fish moves. Can it really tell your fortune, or is their a scientific explanation for the fish’s behavior?

            In this lab, you will use the scientific method to create a hypothesis about the behavior of the fish. You should devise and try several different experiments to test your hypothesis.

 

Procedure

  1. Place the fish in the palm of your hand.

 

  1. Make observations of the fish as it sits in your palm.

 

  1. Place the fish on a piece of paper. Observe the fish.

 

  1. Make a data table and record the results for your group here:

 

  1. Brainstorm some hypotheses about the behavior of the fish. Record the ideas here:

 

  1. Pick a reasonable hypothesis to test. Before you test your hypothesis, try to explain how you think the fish works:

 

  1. Devise some experiments your group would like to try. Describe your procedure and results here:

 

  1. Do your results affirm your hypothesis or not?

 

  1. What makes the miracle fish move?

 

 

Teacher’s notes:

Fortune Teller Fish are inexpensive and easy to order from many scientific supply houses and other sources like http://www.fortunetellerfish.com/ where $20 will buy 100 fish.

 

I tell the students that I will provide them with anything they need to test their hypotheses. I have ready a supply of paper towels, ice, hot plates, Saran wrap, spray bottles, etc. Caution: a wet fish is a dead fish!

 

There is a gel on one side of the fish is hygroscopic and reacts to moisture from the hand. (Lots of info on the web, see: http://www.terrificscience.org/ncw/pdf/Fortune%20Teller%20Fish.pdf ).

 

Even though I use this in AP Biol, it is appropriate for any level high school science. Don’t overuse it though, or kids will already know the explanation!

 

Some kids never figure it out!

 

 


 

Internet Map Project - Earth Science Lab

 

            A map is a flat representation of the earth's curved surface as viewed from space. In the past, cartographers had to rely on ground-based observations and measurements to diagram surface features. Today, the use of high-resolution satellite and airplane imagery helps us draw maps accurately. In this lab, we are going to find an aerial photograph of a familiar site (hopefully, your neighborhood), and compare this with a map of the same site.

 

1. Website - The best website for the aerial photographs is

http://terraserver-usa.com/

Here, you should be able to type in the name of the town where you live, and zoom in to your neighborhood by clicking on the image several times. You may need to occasionally recenter the map by clicking on the arrows on the sides of the image.

 

            Date of photograph:                                                  

 

2. Printout - Print the page with the best image of your neighborhood.

 

3. Map - Get a map of the same area by changing the view button (upper left-hand corner of the screen) from aerial photo to topo map

 

            Date of map:                                                             

 

4. Printout - Print the page with the best map of your neighborhood.

 

5. Evaluate - Tell me something about the image. Is it the way you pictured it would look? Have things changed since the image was taken? How does the map differ from the photograph?

 

 

 

 

6. Other Websites - If you finish, check out these other two great websites that we refer to a lot in this class:

 

http://noaa.gov/ - for weather and climate information

http://usgs.gov/ - for geology and geography information

 

 

 

Teacher’s notes:

As our school is small, we usually display the photos or maps on a large bulletin board in the hallway with the student’s first names only and yarn showing the location of each home on a larger area map.

 

We do this as part of a larger unit on map reading in Earth Science.

 

Many of kids are surprised by how their neighborhood looks from the air!


Don’t skid out of control!

 

 

Background

Ice on roads is extremely dangerous as tyres can’t grip and cars slip and slide into all sorts of accidents.  In freezing weather, salt is often put on roads to stop the water on them from freezing.

 

Problem:

Design an experiment to find out:

            What is the minimum amount of salt that can be used to stop an ice-cube          freezing in the freezer?

 

Materials:

            One ice cube tray, water, salt, balance, spatula, watch glass, 10ml measuring     cylinder.

 

 

Assessment:

  • Full practical report (one for the group)
  • Scientific method
  • Skills of working as a group
  • Practical skills

Running Smoothly

 

 

Background

‘Antifreeze’ is put into the radiators of cars in very cold climates to stop the water in the radiator from freezing.  Antifreeze is an expensive chemical, so it would be useful to know how much should be used.

 

Problem:

Design an experiment to find out:

            What is the minimum amount of antifreeze that can be used to stop an ice-         cube freezing in the freezer?

 

Materials:

            One ice cube tray, water, antifreeze, 10ml measuring cylinder.

 

Assessment:

  • Full practical report (one for the group)
  • Scientific method
  • Skills of working as a group
  • Practical skills

Boy, is that hot!

 

 

Background:

Pure water boils at 100oC.  Different mixtures boil at different temperatures.

 

Problem:

Design an experiment to find out:

            How does the boiling point of water change as different amounts of salt (sodium chloride) are added to it?

 

Materials:

            Bunsen burner, heat mat, tripod, gauze mat, 100ml beaker, thermometer, salt,    spatula, balance, water

 

 

Assessment:

  • Full practical report (one for the group)
  • Scientific method
  • Skills of working as a group
  • Practical skills

Energy to Burn

 

 

 

Background

There are many types of fuels which give us energy.  At camp earlier this year you used methylated spirits in your ‘Trangia’ stoves to cook lunch.  Another type of fuel is kerosene.  You are organising a trek to the Australian Research Base in Antarctica.

 

Problem:

Design an experiment to find out:

            Which fuel would be the best to take on your expedition, bearing in mind the      high cost of transporting fuels to the Antarctic?

 

Materials:

            Methylated spirits, kerosene, water, 10ml measuring cylinder, thermometer, test-tube, test-tube holder

 

Warning:

Fuels can be dangerous if handled carelessly.

Check with your teacher before starting your investigation.

 

 

Assessment:

  • Full practical report (one for the group)
  • Scientific method
  • Skills of working as a group
  • Practical skills

 


Interrelationships of Producers and Consumers

 

 

Interrelationships between organisms in a community are often complex.  However it is possible to look at individual parts of this tangled web.

 

Purpose: To investigate some relationships between autotrophic and heterotrophic organisms in a simple community, in particular the processes of cellular respiration and photosynthesis.

 

Background information: Phenol red is an indicator which shows the presence of an acid or a base.  It changes to a yellow colour in the presence of an acid.  The gas carbon dioxide (CO2), forms an acid when dissolved in water:

 

CO2 + H2O                  H2CO3

 

In this experiment, change in colour of the indicator can be used to indicate, indirectly, the presence of carbon dioxide.

 

Materials and Equipment:

¨      8 test tubes with covers

¨      Test tube rack

¨      4 aquatic consumer organisms

¨      4 pieces of aquatic producer organisms

¨      Pond or aquarium water

¨      Felt-tipped pen

¨      Foil

¨      Phenol red indicator

 

Procedure:

1.                  Number the test tubes from 1-8. Fill each tube with some of the pond water until the water surface is approximately 20mm from the top.

2.                  To tubes 1 and 5 add a consumer organism; to tubes 2 and 6 add a small consumer and a producer; to tubes 3 and 7 add a producer only; the final 2 tubes (4 & 8) should be left with pond water only.

3.                  Add 4 drops of phenol red indicator to each tube.  All tubes should show exactly the same colour.  Record this colour (eg: using coloured pencils).

4.                  Seal each tube.

5.                  When all tubes are watertight, place tubes 1-4 in a brightly lit or sunny situation, though not where the water can become too hot.  If the weather is hot at this time, immerse the tubes in a large body of cooer water, such as that in an aquarium tank, or the consumers may die.

6.                  Cover tubes 5-8 with foil so that no light can enter and place them near tubes 1-4.

7.                  Observe all tubes at the end of the day; and next morning.  Record colours.

8.                  Prepare a suitable results table.

 

Describing colours accurately is difficult.  You would be wise to restrict yourself to the following words: reddish-purple, red, reddish-orange, orange, orange-yellow, or yellow.

 

 

Studying the Data/ Discussion:

  1. Compare your results with those of other groups before interpreting you own data.
  2. Process your results
  3. When discussing data; the colour change indicates whether carbon dioxide is present or not – what does this mean about the rates of respiration and photosynthesis?
  4. Write a thorough conclusion
  5. Evaluate procedures and results.
  6. Suggest improvements to this investigation

 INTERRELATIONSHIPS OF PRODUCERS AND CONSUMERS

TEACHER’S NOTES

 

Interrelationships between organisms in a community are often complex.  However it is possible to look at individual parts of this tangled web.

 

Purpose: To investigate some relationships between autotrophic and heterotrophic organisms in a simple community, in particular the processes of cellular respiration and photosynthesis.

 

Background information: Phenol red is an indicator which shows the presence of an acid or a base.  It changes to a yellow colour in the presence of an acid.  The gas carbon dioxide (CO2), forms an acid when dissolved in water:

 

CO2 + H2O                  H2CO3

 

In this experiment, change in colour of the indicator can be used to indicate, indirectly, the presence of carbon dioxide.

 

Demonstration: Colour changes when phenol red is with

  1. 0.1M ammonia solution
  2. 0.1M hydrochloric acid

 

Materials and Equipment:

¨      8 test tubes with covers (boiling tubes as they are bigger)

¨      Test tube rack (single row so no shadowing)

¨      4 aquatic consumer organisms (pond snails)

¨      4 pieces of aquatic producer organisms (Elodea)

¨      Pond or aquarium water (acclimatise the snails and Elodea for 2 days prior to experiment)

¨      Felt-tipped pen (or labels for each t-tube)

¨      Foil

¨      Phenol red indicator (make up in alcohol as the small amount used won’t affect the snails)

 

Procedure:

  1. Number the test tubes from 1-8. Fill each tube with some of the pond water until the water surface is approximately 20mm from the top.
  2. To tubes 1 and 5 add a consumer organism; to tubes 2 and 6 add a small consumer a a leafy stem of pond weed; to tubes 3 and 7 add pondweed only; the final 2 tubes (4 & 8) should be left with pond water only.
  3. Add 4 drops of phenol red indicator to each tube.  All tubes should show exactly the same colour.  Record this colour (eg: using coloured pencils).
  4. Seal each tube.
  5. When all tubes are watertight, place tubes 1-4 in a brightly lit or sunny situation, though not where the water can become too hot.  If the weather is hot at this time, immerse the tubes in a large body of cooer water, such as that in an aquarium tank, or the consumers may die.
  6. Cover tubes 5-8 with foil so that no light can enter and place them near tubes 1-4.
  7. Observe all tubes at the end of the day; and next morning.  Record colours.
  8. Prepare a suitable results table.

 

Describing colours accurately is difficult.  You would be wise to restrict yourself to the following words: reddish-purple, red, reddish-orange, orange, orange-yellow, or yellow.

 

 

Studying the Data/ Discussion:

Discuss as a class after setting up experiment:

  1. Create hypothesis
  2. What environmental factors were controlled?
  3. Compare your results with those of other groups before interpreting you own data.
  4. Processing data: Convert your results table into a useful graph. Type? Why?
  5. When discussing data;
    1. Describe process of photosynthesis and respiration
    2. the colour change indicates whether carbon dioxide is present or not – what does this mean about the rates of respiration and photosynthesis?
    3. Explain the significance of results of tubes 4 and 8 and other tubes
    4. Relate results to a ‘natural community’. Which tubes resemble real life? Describe relationship shown by these results
    5. What do you think would happen in each tube over a longer period?
  6. Write a thorough conclusion
  7. Evaluate procedures and results.
  8. Suggest improvements to this investigation

 


Bouncing Popcorn

 

You will need:

Newspaper, water, clear glass or cup, vinegar, baking soda, toothpicks, 10 unpopped popcorn kernels, (or sultanas), spoon

 

What to do:

  1. Put the newspaper on the bench.
  2. Fill  the cup ¾ full of  water and then add 60mls of vinegar. Put the cup in the middle of the newspaper.
  3. Add a pinch of baking soda and stir.
  4. Add a few kernels of the popcorn
  5. Add a few more pinches of baking soda
  6. Using a toothpick, poke at the bubbles forming around the popcorn.  Then observe the popcorn kernels as they sink.

 

What to write in your book:

  1. Glue these instructions in to your book.
  2. Record all your observations accurately
  3. Write a hypothesis to try to explain your observations.

 

 

 

 

Bouncing Popcorn

 

You will need:

Newspaper, water, clear glass or cup, vinegar, baking soda, toothpicks, 10 unpopped popcorn kernels, (or sultanas), spoon

 

What to do:

  1. Put the newspaper on the bench.
  2. Fill  the cup ¾ full of  water and then add 60mls of vinegar. Put the cup in the middle of the newspaper.
  3. Add a pinch of baking soda and stir.
  4. Add a few kernels of the popcorn
  5. Add a few more pinches of baking soda
  6. Using a toothpick, poke at the bubbles forming around the popcorn.  Then observe the popcorn kernels as they sink.

 

What to write in your book:

  1. Glue these instructions in to your book.
  2. Record all your observations accurately
  3. Write a hypothesis to try to explain your observations.

 

 

 

 


Design your own experiment

 

 

Problem: 

It is the start of recess and Ms Burke has just poured the hot water onto her t-bag to make a cup of tea.  A student knocks at the staffroom door and wants to see her.  What should she do with her tea to ensure it is hot when she comes back after 10 minutes?  Should she add the milk before she goes or wait and add the milk when she gets back?

 

Design an experiment to find out.

 

 

In pairs, discuss how you could find out.  Use the guidelines to writing up a report and write the heading, aim, hypothesis, materials and method (with a diagram, using the template).  Rule up a results table ready to collect the data next lesson.

You have the equipment in the cupboard under your bench plus:

t-bags, hot water (boiled in a kettle), thermometer, stop watch, milk.

 

 


Lab Report Format

Below are descriptions of the sections that are needed for “writing up” a practical report before you start an experiment  Write the sub-heading in red pen for each new section.  Follow the instructions accurately.

 

Heading: Write “Exp.” ( short for experiment) and then the title of the task.  To the right of the heading, write the date.  Underneath the date, write your partner’s name.

 

Aim:  This is the reason for doing the experiment.  Usually starts of with “To see….” Or “To find out….” etc.

 

Hypothesis:  If your aim was in the form of a question, you write down your ‘educated guess’ as to what might happen in your experiment.  Sometimes there will be no hypothesis.

 

Materials:  This is like the ingredients list.  It is all the equipment that you need to do the experiment

 

Method:  These are the instructions as to what you need to do to perform the task. There should be enough detail so that others can repeat the experiment.  Check that all equipment in the method is also in your materials list.  It should be a ‘fair test’ and have ‘controlled variables’.  Adding a diagram of your set up is good in this section.

 

Results:  This is where you write your observations, data etc.  Before the experiment, we just rule up a table ready to write down what happens.

 

Now you can do the experiment and record your results.  Sometimes you need to present the data using diagrams or graphs.

 

 

 

 

After doing the experiment fill in the following sections:

 

Discussion:  There are usually some questions to answer, based on your results.  You can also make comment on:

§         problems that you had which may have caused your results to be inaccurate

§         some ideas for further investigations

§         any other interesting things that you noted.

 

Conclusion:  This is a statement to describe what you found out in the experiment.  It always relates the results you obtained back to the “aim” of the experiment.

 


Lab Report Format Practice

These 2 pages have each section of a practical report, but they are in the wrong order.  Your task is to follow the instructions on how to present a report, paste each section in order and carry out the experiment.

 

 

1.    Half fill the beaker with water.

2.    Using the spatula, put about 3cm of wax pellets in to a test tube.

3.    Set up the equipment as shown in the diagram.

4.    Heat the wax just until it melts. NO LONGER!

5.    Turn off the Bunsen burner.  Read the temperature and start the stop watch.  (Make sure your eye is level with the thermometer liquid when you do this.)  Put 0 min and the temperature into your data table. 

6.    You will need to read the temperature every minute for 15 minutes.

7.    Clean up – don’t try to remove the thermometer from the solid wax unless your teacher asks you to.

8.    Draw a line graph of your data.

 

 

 

To use a thermometer to measure temperature, learn how to ‘write up’ a practical report and to see what happens to the temperature of wax when it cools.

 

 

 

 

Temperature of wax as it cools

 

 

 

Time (mins)

Temp (°C)

Time (mins)

Temp (°C)

0

 

8

 

1

 

9

 

2

 

10

 

3

 

11

 

4

 

12

 

5

 

13

 

6

 

14

 

7

 

15

 

 

 

 

Test tube, paraffin wax, thermometer, Bunsen burner, retort stand, boss head, clamp, stop watch, beaker, water, tripod, heat mat, gauze mat.

 

 

Describe in words what happens to the temperature.

Try to explain any unexpected results.

………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………

 

 

 

In this experiment we …………………………… ………………… ……………………………………………………………………………………………………………………………………………………


YEAR 11 BIOLOGY

 

Measuring the Vitamin C content in a variety of fruit juices

 

 

 

Criteria:                        DC, DPP, C & E

Due Date:                     _____________________

Relevant IB Topics:      Options A-1  A-2

 

 

BACKGROUND


Vitamin C, also called ascorbic acid, is a water soluble vitamin.  It is a powerful reducing agent that is able to decolourise blue DCPIP (2,6-dichlorophenol indophenol).  The decolorisation of DCPIP can therefore be used to calculate the vitamin C content of a variety of fruit juices.

 

AIM

 

Your aim is to determine the percentage Vitamin C in a variety of juices.

 

MATERIALS


2 x 10cm3 pipettes, 1 cm3 pipettes/syringes, 3 small beakers, small (10mL) measuring cylinders, DCPIP solution, 0.1% ascorbic acid, distilled water bottle, fruit press/ juicer, filter funnel, knife, 2 filter papers.

 

Examples of juices to test:  1 fresh unsqueezed orange, orange juice squeezed 3 days before, bottled orange juice in a transparent glass bottle, orange juice in a carton, orange flavoured drink.

 

PART A

 

METHOD

(1)        Slowly pipette 1 cm3 (1mL) of DCPIP into two 10mL measuring cylinders.

 

Warning DCPIP is corrosive and toxic.  Wash off any spills with plenty of water.

 

Preparation of the controls.

(2)        Take 5 cm3 of the 0.1% ascorbic acid using the pipette.

     Add the 0.1% ascorbic acid drop by drop into the measuring cylinder, gently shake the tube after each drop is added.  As soon as the DCPIP becomes decolourised, note the volume of ascorbic acid that was added.  Wash the pipette and the beaker.

 

(3)        Into the second measuring cylinder, add the same volume of distilled water as ascorbic acid that you added in test tube 1.  Gently shake the test tube and note your observations.


Testing the fruit juices.

(4)        Dilute all the juices to be tested five times  (2mL of juice to 8mL of distilled water).

 

(5)        Into a clean 10mL measuring cylinder add 1 cm3 (1mL) of DCPIP.  To this measuring cylinder, add the first sample of juice drop by drop, gently shake the tube after each drop is added and note the volume added in order to decolourise the DCPIP.  Continue in the same way for the other fruit juices.

 

Do not forget to carefully wash out the beaker, measuring cylinder and the pipette after each juice used.

 

Calculate the concentration of ascorbic acid present in each fruit juice:

 

            % ascorbic acid =

 

 

 

 

YOUR TASK

 

Ø      Create and complete an appropriate format for data collection

Ø      Discuss and compare the different presentations of orange juice and their Vitamin C content.

 

Ø      What do your results suggest about the way in which Vitamin C is broken down in foodstuffs?

 

Ø      Write a conclusion including limitations/weaknesses in this practical investigation.  How could you improve this experiment?

 

 

 

 


Temperature and Yeast Respiration

 

RELEVANT IB TOPICS:   C.2.7  AHL 7.2    OPTION C.3

 

 

BACKGROUND

 

Yeast cells contain enzymes that decompose sugar molecules to produce chemical energy, carbon dioxide gas and ethanol (alcohol), in a chemical reaction called FERMENTATION.

 

The carbon dioxide gas is released as bubbles which can be detected by limewater which turns milky in the presence of carbon dioxide.

 

AIM

 

To observe and measure the effect of temperature on the rate of respiration in yeast cells.

 

MATERIALS

 

  • Test tube with rubber stopper
  • Test tube
  • Limewater solution (freshly made)
  • 500 mL beaker
  • Plastic tubing with dropper bottle applicator
  • Thermometer (-10 – 100oC)
  • Yeast – sugar solution (100 mL)
  • Bunsen burner
  • Tripod
  • Gauze
  • Stopwatch

 

PROCEDURE

 

1.         Set up apparatus as in diagram.

2.         Allow the yeast-sugar solution to adjust to the temperature of the water bath. (About 5 minutes)

 

3.         Count the number of bubbles exiting the delivery tube over 30 s.

4.         Record the temperature and the number of bubbles in a table.

5.         Heat the water bath to 10oC higher temperature and repeat steps 3 and 4.

6.         Repeat step 5 until 80oC is reached.

7.         Record results in a suitable format for analysis.


DIAGRAM

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 


YOUR INVESTIGATION

 

On ruled A4 sheets of paper, analyse your results (record accurate results in appropriate formats – graphs, tables etc.) for analysis, giving a valid conclusion with explanation of the results.  Evaluate the materials used, procedure followed and results obtained including errors, weaknesses and limitations.  Give appropriate suggestions to improve further the investigation.

 


YEAR 12 BIOLOGY

 

Name: _____________________________________ Date: ___________ Due: ___________

 

Human Kidney Output

 

 
 


TOPICS:                     5.5, 15.1

 

CRITERIA:                DA, EV

 

INTRODUCTION:

 

The levels of water and salts in an animal remain constant despite changes in water intake and output.  However, blood and urine composition changes relate to diet, with the kidneys helping to maintain a constant internal environment.

 

AIM:

 

To investigate the way in which the human kidneys assist in regulating the internal composition of the body.

 

PROCEDURE:

 

The following table shows the amount of seven substances found in three related areas in a human with a normal balanced diet

 

A  Amount of substances filtered into the kidney tubules in the time necessary to produce 1 L of urine (about 18 hours).

 

B          Amount of substances which leave the kidneys via the renal vein in the same time.

 

C         Total amount of substances in the urine.

 

 

Blood

Constituent

Amounts filtered into Kidney Tubules

(A)

Amounts in Renal Veins

(B)

Amounts in Urine

 

(C)

water

100 L

99 L

1 L

chloride ions

370 g

364 g

6 g

glucose

70 g

70 g

0 g

urea

30 g

10 g

20 g

uric acid

4 g

3.5 g

0.5 g

calcium ions

10 g

9.85 g

0.15 g

creatinine

(a nitrogenous waste)

1 g

0 g

1 g

 


An experiment was carried out where three groups of five students were placed on strict diets for 48 hours.  At the end of this time they gave a urine sample which was tested for the seven substances listed in the table above.

 

Diet A                          High protein – low carbohydrates

Diet B                          Low salt

Diet C                          High carbohydrates – low protein

 

 

YOUR INVESTIGATION:

 

Your task is to produce expected average “results” for the students of each group.

 

These results are NOT to be qualitative but quantitative, with the basis being the table of results supplied.

 

You are to evaluate the four diets offering explanations for the results obtained based on your knowledge of homeostasis.

 

Discuss possible errors, limitations and weaknesses in the procedure.

 


YEAR 11 BIOLOGY

 

Movement of materials through cellular membranes

(D)

 

Purpose:                      To investigate the movement of materials through the cell membrane of plant cells.

 

Requirements:            (per student or pair of students)

                                    Microscope

                                    Cavity slide and coverslips

                                    Salt solution (0.8 M NaCl)

                                    Eye dropper

                                    Paper toweling

                                    Spirogyra, or other suitable living plant cells

 

Procedure:                  1.      Place a few strands of Spirogyra (or alternative) in a drop of distilled water on a cavity slide.

                                    2.      Examine under low and then high power.  Draw a labelled diagram of a cell.  If you cannot see the cell membrane clearly, indicate where you think it is.

                                    3.      Irrigate the slide with salt solution (if necessary refer back to Activity S2).

                                    4.      Observe and record any changes in the cells that occur in the next few minutes.

                                    5.      Draw another labeled diagram of a cell in salt solution.

                                    6.      Now irrigate with distilled water and record what happens.

 

Questions:                   Q1.    How do your results help you to decide whether water moved into or out of the cells when they were surrounded by salt solution?

                                    Q2.    In which direction do your results indicate that the water moved after the salt solution was washed away by distilled water?

                                    Q3.    Does the cell membrane or the cell wall hold in the cell contents?  What is your evidence?

                                    Q4.    Animal cells, such as red blood cells, swell up and burst if placed in distilled water.  Would you expect plant cells to burst if left in distilled water?  Explain.

                                    Q5.    Name the mechanism which brings about movement of water through a cell membrane in this activity.

 

Cells before addition of Salt

Cells after addition of Salt

 

 

 

 

 

 

 

 

 

 

 

 

 

IB BIOLOGY EXPERIMENT

 

Enzyme – Rate of Reaction

 

 

Teacher Demonstration

 

Liver contains the enzyme catalase which speeds up the reaction:

            Hydrogen peroxide à Water       + Oxygen gas

                       2H2O2            à  2H2O(l)  +        O2(g)

 

Method:

 

1.         Grind liver with sand in a mortar and pestle to produce juice.

 

2.         Cut filter paper into 1 cm x 1 cm squares.

 

3.         Into 1L glass measuring cylinder add 1000 mL distilled water.

 

4.         To the measuring cylinder, add 1 drop* 35% Hydrogen peroxide.

            (* This may need to be adjusted.)

 

5.         Dip filter paper square into the "liver juice".  (Shake the paper to remove any excess.)

 

6.         Drop soaked filter paper into the measuring cylinder.

 

7.         Using a stop watch, record the time taken for the paper to sink and return to the surface.

 

Reasoning

 

The rising of the paper is due to the production of oxygen (O2) gas.

 

Application

 

You can vary the experiment so that students research different components of the theme; such as:-

 

Ø      temperature variation

Ø      pH of water

Ø      different animal livers

o       warm blooded vs. cold blooded

Ø      liver conditions, eg. boiled, aged

Ø      concentration of hydrogen peroxide

 

 

 


Periodic Table Project

 

Objective:

  • You will become familiar with the periodic table and its usefulness in chemistry.
  • You will become an expert on one of the elements on the periodic table.
  • You will understand everything there is to know about your element and present it to the class through a visual medium.

 

Assignment Guidelines:

  1. Use poster board, construction paper, markers, colored pencils, glitter, and any other art materials that you bring in to class.  (Basic materials will be supplied by your instructor.)
  2. Be creative and imaginative!
  3. Organize your material on the poster board for easy visual access.
  4. Neatness counts.  Use a ruler to draw straight lines, draw or print out pictures from the computer, stencil and write clean and clear.
  5. Use and site at least three different internet sources and two book sources for your information on your element.  (Always reference where you found the information!)

 

Description Guidelines:

1.      Include the physical properties of the element.  Description of what the element looks like.  Elements density (g/cm3).  Metal, non-metal, or metalloid.

2.      Include chemical properties of the element.  Description of how the element reacts with other elements such as: whether the element is corrosive, combustible, or flammable.

3.      Show the number of protons, neutrons, and electrons the element has.

4.      Show the atomic number of your element.

5.      Show the elements relative abundance on earth such as: is the element rare or common?

6.      List who discovered your element.

7.      List where it was discovered.

8.      List when it was discovered.

9.      List how it was discovered.

10.  List at least 3 things that your element is used for.

Rubric for grading Periodic Table Project

 

Excellent work & all guidelines followed

3

Good work & most guidelines followed

2

Poor work & some guidelines followed

1

Missing most or all work & guidelines not followed

0

Assignment

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Description

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Presentation

 

 

 

 

                                                                                                            Total

/48

 

Rocket Activity

 

Introduction:

The goal of this activity is to understand the basic concepts of rocketry.

Rocketry is not a new concept, however, it is only recently that the science fiction of Jules Verne has become the reality of the scientists at NASA.   Research the following people and their contribution to rocketry.

 

·        Jules Verne

 

 

 

·        Robert Goddard

 

 

 

·        Von Braun

 

 

 

 

Procedure:

  • In order to track the altitude of the rocket, use (or create) an elevation tracker.  It can be made by hanging a string from the pivot point of a protractor with a weight (a washer) tied to the end of the string. 
  • The observer stands a distance (D), 100 meters from the launch pad.
  • Using the elevation tracker, site the rocket down the flat side of the protractor.
  • Track the rocket from launch to apogee (the highest point of flight).
  • Let the string hang down until the rocket reaches apogee, then clamp it with your finger at apogee.
  • The string now indicates the elevation angle of the rocket at its highest altitude.  Call this angle (A).
  • Calculate your rocket’s altitude (H).  The rocket’s altitude is equal to the distance from the launch pad multiplied by the tangent of the elevation angle.
  • H = D x tan(A)

 


Data & Observations:

Data Table for Rocket Activity

 

Trials

Mass of Engine before launch

(g)

Mass of Engine after launch

(g)

Distance from launch pad

 

(m)

Angle of rocket at apogee

 

(º)

Maximum height rocket traveled (m)

1

 

 

 

 

 

 

 

 

 

2

 

 

 

 

 

 

 

 

 

3

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Questions:

  • Using Newton’s Laws of Motion, explain why the rocket travels upward.

 

 

 

 

 

 

 

  • Explain what happened to the mass of the rocket engines after launch.

Save the Egg!

 

Your mission, should you choose to accept it (actually, you don’t have much choice), is to design an egg holder to protect an egg dropped from a minimum of 5 meters.  You will have three days to design and build your egg holder.  The holder needs to protect the egg from cracking.  You must work efficiently with your teammates to build your egg holder with the limited material available.  Your team will be allowed one trial run form a height of two meters and one graded run from a minimum height of 5 meters.  Each team will consist of 3 people, a control engineer, a materials engineer, and an industrial engineer.

 

Control engineer: In addition to the common goal of preventing the egg from cracking, you have the added responsibility of getting the egg holder to hit the target.  The closer your egg lands to the bull’s eye, the more points awarded.  A list of the points for each zone is given and ten points will be automatically deducted for a cracked egg.

 

Materials engineer: In addition to the common goal of preventing the egg from cracking, you have the added responsibility of minimizing the cost of the material.  You can purchase materials from the teacher using physics money.  You have a maximum budget of 50 Physics Bucks.  A price list for the different materials is given.  All purchases are final, no exchanges or returns.

 

Industrial designer: In addition to the common goal of preventing the egg from cracking, you have the added responsibility of making your egg holder as aesthetically pleasing as possible.  The more pleasing your egg holder is to the eye (before being dropped), the more points your team will receive.

 

Materials Cost list:                                physics money                                              physics money


  • Paper cup                                             5
  • Plastic cup                                            5
  • Styrofoam cup                                      5
  • Styrofoam bowl                                    5
  • Styrofoam plate                                    5
  • Ziplock bag (small)                               3
  • Plastic bottle                                         5
  • Shredded paper (handfull)                    10
  • Packing peanuts (handfull)                    10
  • Bubble wrap (1 rectangular piece)    10
  • Napkin                                                 1
  • Cloth (5 cm2 piece)                               3
  • Egg carton (4x4 piece)  3
  • Balloon                                     5
  • Popsicle stick                           1
  • Coffee filter                              1
  • String (1 meter)                        3
  • Masking tape (1 meter) 3
  • Twist tie                                   1
  • Paper clip                                 1
  • Clay (small lump)                      3
  • Styrofoam block                       5
  • Ziplock bag (big)                      5

 


 

Save the Egg Scoring Sheet

 

Control Engineer:________________________________________

 

 

Materials Engineer:______________________________________

 

 

Industrial Designer:______________________________________

 

 

Assistant Engineer:_______________________________________

(If applicable)

 

 

Scoring Rubric

 

  1. Egg Integrity:
    • 50 points for no breaks or cracks                                                          ________/50
    • 40 points for crack under 1 cm in length
    • 30 points for other cracks
    • 20 points for major cracks, but still together
    • 10 points for a runny egg

 

  1. Material cost:
    • For every unused physics dollar your team will receive a point,      _________/30

30 points maximum

 

  1. On target:
    • 30 points for bulls eye                                                             _________/30
    • 20 points within ½ meter of bulls eye
    • 10 points within 1 meter of bulls eye
    • 0 points outside of scoring area

 

  1. Egg holder aesthetics:
    • Maximum 20 points                                                                           _________/20

 

 

Total:           _________/130


Name:                                                                                                              Date:

 

 

Fluids Lab

 

Objective:

Determine the resistive force (Fr) acting on a small spherical object as it falls through an unknown viscous fluid.  Utilize Stoke’s Law, Archimede’s Principle, and Newton’s second law to obtain the unknown resistive force.

 

Equipment -    graduated cylinder

-         rubber stopper with hole

-         small diameter glass tube

-         unknown fluid (rf  given )

-         ball bearings (rbb given)

-         meter stick

-         stopwatch

-         micrometer

 

Archimede’s Principle: The buoyant force (Fb) is equal to the weight of the displaced fluid.

                       

Fb = m g = rf g V

Stoke’s Law: The resistive force (Fr) is equal to the product of the viscosity of the fluid (h), the radius of the small object (r), the speed of the object (v), and a constant (6 p).

 

Fr = 6 p h r v

Procedure: Concisely describe the method which you obtained the resistive force.  Include any data which you recorded during the lab.

 

 

 

 

Question 1: Would the value for Fr be increased, decreased, or stay the same if the object falling were hollow?  Explain your answer

 

 

 

 

 

 

 Question 2: What differences would one find if the same experiment was done atop Mount Everest (8850m)?  At the Dead Sea shore (400m below sea level)?  Explain your answer.

 

 

 

 

 

 

Question 3: Would temperature affect the Fr in this experiment?  Explain your answer.

 


Newton’s Laws Worksheet

 

  1. Determine your body weight in pounds, Newtons, and dynes; and your body mass in kilograms and grams.

 

  1. A traffic light weighing 10 kilograms is suspended from a vertical cable tied to two other cables that are fastened to a support.  The upper cables make angles of 37 ˚ and 53˚ with the horizontal. Find the tension in each of the three cables.

 

  1. Travis and Emily are pulling a boat through the water.  Each exerts a force of 600 N directed at a 30 ˚ relative to the forward motion of the boat.  If the boat moves with a constant velocity, find the resistive force exerted on the boat by the water.

 

  1. John’s 2000 kg car is slowed down uniformly from 20.0 m/s to 5.0 m/s in 4.0 seconds.  What average force acted on the car during this time and how for did the car travel during the deceleration?

 

  1. Larkin drops out of school and goes to work on the docks loading crates on a ship.  He finds that a 20 kg crate, initially at rest on a horizontal surface, requires a 75 Newton horizontal force to set it in motion and a horizontal force of 60 Newtons is required to keep it moving with a constant speed.  Find the coefficient of static and kinetic friction between the crate and the floor.

 

Fast Crystallization

 

Crystal growth can be observed under magnification in the following procedure.

 

1.  Make super-saturated solutions of the following salts (I have done this for you):

           

            magnesium sulfate

            aluminum-potassium sulfate

            copper sulfate

            sodium chloride

 

            To make the super-saturated solution, heat distilled water in an erlenmeyer flask (do not boil).  Add the salt and agitate until completely dissolved.  Continue adding salt until no more will dissolve.  When the solution is cooled, you will have a saturated solution. 

 

2.  When the solutions are cooled completely:

 

            1.  drop 1 or 2 drops on a glass slide

            2.  add 1 drop of alcohol to drop vapor pressure

            3.  observe on low magnification, how the crystals grow.

 

            In a paragraph or two, describe the sequence of events as the crystals grow.

 

3.  In the circles provided below, draw what you see.  Be sure that you label your drawing with the name of the salt that is in solution. 

 

 

Sample:_____________________                  Sample:_________________________

 

 

 

 

 

 

 

 

 

 

 

 

 


                                                                                   

                                                                                               

                                               

 

                                                                                                           

      Sample:___________________

 

Answer the following questions after observing crystals grow under magnification.  Use white lined paper and complete sentences.

 

 

1.  For each salt crystal you observe, describe the salt using normal light (using the regular microscopes).  When you are finished, look at the sample using the petrographic microscope in front of the room describe what you see.   What is the difference between the two samples?

 

2.  What is polarized light?

 

3. What does it do to the salt samples?

 

4.  In a paragraph or two, describe what you saw.  How the crystals grow.   Include a discussion on time and development of the crystalline form.

 

5.  a) Do all the crystals have the same shape?

      b) Describe how the crystals are similar or different.

 

6.  Does the chemical formula influence the shape of the crystals formed?

 

7.   a) What are growth surfaces?

      b) What are cleavage surfaces?

      c) Are you seeing growth surfaces or cleavage surfaces?

 

8.  What is the definition of a mineral?

 

9.  In nature, minerals are found in both massive and crystalline form.  Crystalline form looks like crystals.  Massive form frequently looks like sugar that has been stuck together.  Which form did you observe under the microscope?

 

10.  a) How is a pearl made? 

     b) Is a pearl a mineral?

     c) Why or why not?

 

 

 

            The purpose of this workshop is to demonstrate how crystals can be grown under a microscope so that students can observe crystal growth.  Paticipants will cool supersaturated solutions of several salts of different crystal systems using a student monocular microscope and observe similarities and differences of salt crystals as they grow.  After observing crystal growth of selected salts, students will be able to answer the following questions:   Do all the crystals have the same shape?  Does the chemical formula influence the shape of the crystals formed?  How does time influence size of crystals?  With the addition of a polarizing microscope optic axes can be explored.

            This lab exercise can be related to crystal growth in igneous rocks and mineral classification.  Students will find the exercise to be engaging.

 


EXPERIMENT:         

Planning an Experiment – Capillary Action

 

 

Candidate Name ___________________________________

 

Candidate Code ___________________

 

 

RELEVANT IB TOPIC:    CORE 4

 

 

In this experiment you will be assessed on the following criteria:

 

Skills

Criteria

Complete (C)

Partial (P)

Not at all (N)

Level

(0 – 3)

Planning (a)

§           Defining problem or research question

§           Formulating an hypothesis or prediction

§           Selecting variables

 

 

 

 

 

 

 

 

Planning (b)

§           Selecting appropriate apparatus or materials

§           Designing a method for the control of variables

§           Designing a method for the collection of sufficient relevant data

 

 

 

 

 

 

Your task is to plan an experiment to investigate a factor affecting the height of a liquid in a capillary tube.

 

 


 

EXPERIMENT:

Investigating a Drop of Liquid

 

 

Candidate Name ______________________________________

 

Candidate Code _____________________

 

 

RELEVANT IB TOPIC:  CORE 5

 

In this experiment you will be assessed on the following criteria:

 

 

Skills

Criteria

Complete (C)

Partial (P)

Not at all (N)

Level

(0 – 3)

Planning (a)

§           Defining problem or research question

§           Formulating an hypothesis or prediction

§           Selecting variables

 

 

 

 

 

 

 

 

Planning (b)

§           Selecting appropriate apparatus or materials

§           Designing a method for the control of variables

§           Designing a method for the collection of sufficient relevant data

 

 

 

 

 

 

Your task is to plan and carry out an experiment investigating a drop of liquid.

Your proposal is to be submitted in one week. 

An equipment list is to be submitted with your proposal. 

Standard laboratory equipment is available for your use.

 

 

 


 

Factor affecting stream of liquid changing into droplets

 

 

Candidate Name _______________________

 

Candidate code ____________

 

 

RELEVANT IB TOPIC:      In this experiment you will be assessed on the following criteria:

 

Skills

Criteria

Complete (c)

Partial (p)

Not at all (n)

Level

(0 – 3)

Planning (a)

§           Defining problem or research question

§           Formulating an hypothesis or prediction

§           Selecting variables

 

 

 

 

 

 

 

 

Planning (b)

§           Selecting appropriate apparatus or materials

§           Designing a method for the control of variables

§           Designing a method for the collection of sufficient relevant data

 

 

 

 

 

 

 

Task

Design an experiment looking at a stream of liquid changing into droplets.

 

Note you will not be required to actually perform these experiments. This task will be used to assess your ability to plan and design experiments.

 


 

Using Hess' Law

(III)

 

 

Candidate Name _____________________________________

 

Candidate Code ___________________

 

 

RELEVANT IB TOPIC: 6.3.1

 

In this experiment you will be assessed on the following criteria:

 

Skills

Criteria

Complete (C)

Partial (P)

Not at all (N)

Level

(0 – 3)

Data Collection

§          Collecting and recording raw data

§          Organising and presenting raw data

 

 

 

 

 

 

 

Data Processing and Presentation

  • Processing raw data
  • Presenting processed data