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Ms. E. Fenech Imbroll Biology PracticalsExperiment 1: Osmosis Investigation : A shipwrecked sailor is stranded on a small desert island with no fresh water to drink. She knows she could last without food for up to a month, but if she didn’t have water to drink she would be dead within a week. Hoping to postpone the inevitable, her thirst drove her to drink the salty seawater. She was dead in two days. Why do you think drinking sweater killed the sailor faster than not drinking any water at all.

1. Objective. To determine the cause of the sailor’s death, we will determine the effects of salt water on slices of potato. Our assumptions is that potato cells will behave like sailors cells in her body.

2. Background knowledge:

What scientific knowledge can you use to help you ? (include book references)

3. Planning Method

Selecting the most suitable apparatus

What equipment do I need? Make a list Have I selected the best instruments to get accurate results?

Deciding the number and range of your readings

What am I going to observe/measure? How many observations/measurments do I take? (eg. Four is the minimum of readings if

you plan to show your results on a graph) What range of value will give suitable results? How will I record the results clearly and accurately? (eg. In the form of a table).

Fair test

How can I make a fair test? What are the key factors in this investigation? What am I going to change (independent variable) How will I change it? What factors am I going to keep the same? (control variables) How can I make sure that they remain the same?

Safety

Is the plan a safe one? (eg. You should find out if any chemicals that you plan to use, or any products that might be formed in your tests, are dangerous in any way).

Make sure the teacher checks the plan.

4. Predictions: What am I investigating (trying to find out)? What do I predict will happen?(Base your prediction on the science you know) Why do I think this will happen?

5. Analysing your evidence and drawing conclusions Final questions (in conclusion)

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Ms. E. Fenech Imbroll Biology Practicals What happened overnight to the potato slices? Why did it happen? Is diffusion or osmosis responsible for changes in length of the potato slices? Define both

these terms. Which of the three solutions is isotonic to the potato ? How do you know this? Define hypertonic, isotonic, and hypotonic Why did the sailor die more quickly drinking salt water than not drinking at all? What do you think killed the sailor.

6. Evaluating your evidence and Critique on own experimental method

Having drawn your conclusions, you should know think about the quality of your investigation. Ask yourself these questions:

Were my results accurate? Were there any anomalous (unusual) observations/measurements? What were these due

to? Should I have repeated some tests to get more reliable results? Did I get a suitable range of results? Are the results still good enough to draw a firm conclusion? Why do you think this? If there is a pattern in my results, is it only true for the range of values I use, or would the

pattern continue beyond this range? Comment on any improvements you could make to: The practical steps The accuracy of the results/readings The reliability of the results (eg. Would you get the same results if you were to repeat your

tests again?)

Has this investigation any ideas for further work?

To obtain more evidence To extend the investigation in order to tackle any other aspects of the original question. If

so write about them. Consider planning a new investigation.

7. References

Experiment 2: Investigate the effect of water, temperature and light on germination

Aim: to find the effect of water temperature and light on germination

Materials/Equipment

Seeds e.g. radishDistilled water4 Petri dishesAbsorbent cotton wool

2 ThermometersIncubator (25 °C)Fridge ( 4 °C)Labels

Procedure

1. Familiarise yourself with all procedures before starting. of 11

Ms. E. Fenech Imbroll Biology Practicals2. Set up the four petri dishes with a wad of absorbent cotton wool in each.3. Label the dishes A, B, C, D.4. Place 10 seeds in each dish.5. Leave dish A outside in light, but leave the cotton wool dry - seeds lacking water (but have

light and suitable temperature)6. Wet the cotton wool in each of the other dishes.7. Place dish B in the fridge - seeds lacking a suitable temperature (but have light and water)8. Place dish C in a cupboard in darkness-seeds with water, oxygen, suitable temperature (but

no light).9. Place dish D outside in light-seeds with water, suitable temperature and light.10.Check the dishes daily for 2 3 days.11.Record the results.

Result

DishCondition

Germination ResultsLight WaterSuitable

temperature

A X XB X XC X XD X X X

Errors and Precautions: Radish seeds are recommended, as they usually germinate after 24 hours in ideal conditions. Some seeds are not easily available all year round. March/April is a good time to buy them. The cotton wool only needs to be moistened, not saturated. Ensure that the cotton wool is absorbent.

Conclusion:What is germination?What are the conditions required for germination?Mention each condition required, and explain in detail.Could the effect of oxygen on germination be investigated? What could be done to do this next time? (anaerobic jar etc….)http://www.curriculumonline.ie/en/Post-Primary_Curriculum/Senior_Cycle_Curriculum/Leaving_Certificate_Established/Biology/Biology_Support_Materials/Prescribed_Activities/Detailed_Templates/Investigate_the_effect_of_water,_oxygen_and_temperature_on_germination.html

Experiment 3: Animal Classification practicalAim: To draw biological diagrams of animal specimens

Apparatus: Several preserved animal specimensA4 paperSharp HB pencil

Method:1. Get a preserved animal specimen and draw ONLY what you’re seeing.2. Using books and notes to help you label and annotate the diagram.3. On each sheet write :

A) Name and Surname, Class, DateB) KingdomC) PhylumD) ClassE) Species?F) Magnification

4. Find some information about the importance of the classification system5. Find some information about each phylum and class and/or species.

Errors and precautions: of 11

http://www.curriculumonline.ie/en/Post-Primary_Curriculum/Senior_Cycle_Curriculum/Leaving_Certificate_Established/Biology/Biology_Support_Materials/Prescribed_Activities/Detailed_Templates/Investigate_the_effect_of_water,_oxygen_and_temperature_on_germination.html



Ms. E. Fenech Imbroll Biology PracticalsHow did you handle the specimens?How did you draw the diagrams?How did you ensure that your diagrams were neat?

Conclusion:

Find some information about the importance of the classification system. Why is it important?Who came up with the current system?What is the binomial system?

What are the characteristics of the animal kingdom?What are the characteristics of your phylum/class/species? (relate structure to function).

References:Include any references that you used to do your research.

http://ashvital.freeservers.com/biological_classification.htmhttp://en.wikibooks.org/wiki/General_Biology/Classification_of_Living_Things/Classification_and_Domains_of_Lifehttp://www.qldscienceteachers.com/junior-science/biology/classification-of-organisms

1. Snake and lizard

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http://www.qldscienceteachers.com/junior-science/biology/classification-of-organisms

http://en.wikibooks.org/wiki/General_Biology/Classification_of_Living_Things/Classification_and_Domains_of_Life

http://ashvital.freeservers.com/biological_classification.htm

Ms. E. Fenech Imbroll Biology Practicals

2. Crab (crustaceans)

3. Mollusc

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4. Bettle

5. Fly 6. Dragonfly

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7. Grasshopper

8. Fish

9. Spider

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10. Echinoderm (brittle stars and sea urchins)

Experiment 4: Effect of Leaf Surface and transpirationTitle: To find which surface of a leaf loses more water vapour by Transpiration.

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Ms. E. Fenech Imbroll Biology PracticalsAim: To find whether transpiration occurs most from the upper or lower surface of the leaf.

Materials & Apparatus: 4 leaves, Vaseline, plasticine, marker.

Method:

1. Obtain 4 leaves of approximately the same size. 2. Lay them over a piece of newspaper over the laboratory bench.3. Treat and label each leaf as follows:

- Leaf A: smear a thin layer of Vaseline on the lower leaf surface only.- Leaf B: smear a thin layer of Vaseline on the upper leaf surface only.- Leaf C: smear a thin layer of Vaseline on both surfaces.- Leaf D: Do not smear Vaseline on either surface.

4. Place the four leaves in a piece of plasticine. Piece of plasticine should be big enough to hold each leaf upright.

5. Weigh each leaf and record the mass in the table below.6. Place all the leaves in a sunny place in the laboratory e.g. near a window. 7. Weigh all the leaves again after 2 days.Results:

TABLE Leaf A Leaf B Leaf C Leaf D

Initial mass (grams)Final mass (grams)

Difference in mass (g)

GRAPH:

Plot a bar graph with the following results (leaf against difference in mass)

Diagram:

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Discussion:

1. From which structures is water lost from a leaf surface?2. In what way would you expect a layer of Vaseline to effect evaporation due to transpiration

from a leaf surface? How does Vaseline produce this effect; is it permeable or impermeable?

3. Which of the four leaves took up the least water and most water? Why do you think this happened?

4. Explain the difference in the result obtained for Leaf A and Leaf B. Which of them lost the greater amount of water? What characteristic of the upper and lower epidermis of a leaf caused this difference?

5. Why was it necessary to use leaves of the same size?

Conclusion:

1. What can you conclude from this experiment?2. Does the large amount of stomata on the lower epidermis affect the amount of water lost

during transpiration?3. How was this proved in this experiment?

Experiment 5 – Flower Structure

Aim: To observe the internal and external structures of the flower

Materials used: Hand lens, flower, white tile

Method:1) Obtain a large flower and examine it, using a hand lens. Examine the four whorls which compromise the flower. First, look for the sepals on the flower and make observations.2) The petals compose the next whorl of flower structures. State the colour and shape of the petals.

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Ms. E. Fenech Imbroll Biology Practicals3) Carefully remove the petals of the flower to reveal the stamens. Observe the number and shape of the stamens. Measure the length of the filament.4) Using a magnifying glass examine the anther and touch it with the tip of your finger. Record what is observed.5) Carefully remove the sepals and stamens. Name the structure which is observed.Measure the length of the style.6) Cut this structure to examine the ovary.

Precautions:How did you handle the razor?How did you handle the flower?

Results:Draw diagrams of i) an external flower and ii) a half-flower

Discussion & Conclusion: What are the features of this particular flower? (dicot/monocot, male/female?) What is the purpose of having petals which are colorful and fragrant? Why is the stigma sticky? What did you feel when you touched the anther? What is this? How long was the filament/style. Which was the tallest? Include the function of each observed structure

Experiment 6 – Fruit Structure

Aim: To observe the external and internal structure of the fruit

Apparatus: Knife/Fruit

Method:1. Obtain a number of fruits and observe any flowering parts which are present externally.2. Cut each fruit longitudinally to show the presence of the seeds.3. Draw and label diagrams of the outer structure and cross sections of each fruit.

Precautions:** Handle knife with care

Results: Draw and label diagrams of: (i) outer structure and (ii) cross section of each fruit

Discussion & Conclusion: How can we tell that the items observed are fruit rather than vegetables? What is the most important function of fruits? Do you notice any differences between the fruits observed? What are the functions of the observed and labelled flower parts?

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