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 - CO₂in 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 K_aofweak acids and K_b 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. H₂SO₄acid 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

KMnO₄can be standardised by titration witha standard solution of sodium oxalate, Na₂C₂O₄

The oxalate, C₂O₄^2- ions will be oxidised to CO₂

Using half equations write the equation for the redox reaction between C₂O₄^2-and MnO₄^-

^{___________________________________________________________________________________________________________________}

^{______________________________________________________________________________________________________________}/2

Calculate the mass of Na₂C₂O₄required 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 KMnO₄solution.

Standardisation of KMnO₄solution

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 KMnO₄solution by titration with 20.0 mL samples of the standardised Na₂C₂O₄solution.

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, Na₂C₂O₄solutioninto conical flask

5. Add about 20 mL of diluted H₂SO₄

6. Fill the burette with the provided KMnO₄solution

7. Put a thermometer in the conical flask containing the Na₂C₂O₄solution. 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

_____________________________________________________________________________

Data: part 2:

Steel wool: Mass g

H₂SO_4: Volume and concentration mL & M

Observations of reaction: smelly, bubbles , milky

Na₂C₂O₄: Mass g

Volume mL

Colour

Titration of KMnO₄with 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

SCN^‑ions

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.

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:

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

Method:

go to this web site
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

% of total

100%

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.

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

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:

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)
Place the egg in 5% NaCl solution and leave for 10 minutes – ensure that the egg is fully covered.
Remove – dry and reweigh the egg. Record any other observations
Place the egg in 10% NaCl solution for 10 minutes – ensure the egg is fully covered.
Remove, dry and reweigh the egg. Record any other observations.
Place the egg in the distilled water and leave for 10 minutes – ensure that the egg is fully covered.
Remove, dry and reweigh the egg. Record any other observations.
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 1^OC is 42 J. Thus is 10 ml of water is raised by 10^OC 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

Total marks _____ /16

Valence of Iron

Part 1 (to be done prior to class experiment)

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

Back to the Iron(II) solution:

Data: /3

Le Chatelier’s Principle.

Calculate the mass of Na₂C₂O₄required to make up 250 mL of a 0.05 M solution.