CLINICAL SUPERVISION



S.H.S.S. SCIENCE DEPARTMENT

BIOLOGY CSEC SBA : LAB 6

DATE: 6 / 12/ 18 TEACHER: Mrs. L.Cowie-Clarke SKILLS ASSESSED: A/I

TITLE OF LAB: Osmosis

Aim: To investigate the effect of osmosis on plant tissues placed in different solutions

Apparatus:

Potato borers 2 Measuring cylinder (25ml)

3 petri dishes Scale

Rulers Solutions A and B

Method:

1) Using the potato borer, drill 6 strips of potato. Take care to maintain lengths. Place 2 strips each into the 3 petri dishes labelled A, B and C.

2) Measure the length and Masses of each potato and find the average for each petri dish. Make observations about texture and colour of potato strips.

3) Add solution A into Petri dish A until it completely covers the potatoes. Cover the petri dish. Repeat for Solution B. Leave Petri Dish C exposed to the air.

4) After 30 minutes removed Potato strips from solutions, gently blot them on paper towels. Remeasure their mass and length. Calculate averages. Observe any changes in colour and texture

Results:

1. Record results in a Table in your lab book like the one below except you will write Solution A and Solution B (instead of water and Salt Solution)

2. Calculate % difference calculations for mass and length using the formula

(final - initial) x 100% / initial

TABLE SHOWING RESULTS OF EXPERIMENT 

TO DEMONSTRATE OSMOSIS USING POTATO STRIPS

[pic]

DISCUSSION Points

✓ Theory behind osmosis: definition, use of terminologies hypertonic, hypotonic and isotonic.

✓ Include hypothesis: what are some reasonable expected results and why (e.g If the potatoes are placed in a hypertonic solution then it is expected that …………will occur)

✓ The importance of the apparatus you used.

✓ Explain MAJOR observations ( do NOT repeat method)…you need to LINK the theory with what you ACTUALLY saw and felt

o Which solution would you say was hypertonic, and which hypotonic?

o Explain what happened to the potatoes left in air (do not describe, this was already done in results)

✓ DO the results meet your hypothesis, if No then try to explain why not

✓ Look back at your aim and make clear statement addressing this aim.

These are merely to guide you with your discussion and are not to be answered in a question and answer format in your scientific lab-write up!!!!

Limitations- one or two sentences: what would have prevented you from gathering perfect data

Sources of Error- one or two sentences: Linked to your limitations. What errors are there in the results based on your limitations

Reflection:

Relevance between the experiment and real life (Self, Society or Environment)

Impact of knowledge gain from experiment on self.

Conclusion- MUST be related to your aim: concise statement of the MAIN finding/observations after analysing your results. Whatever is stated here must have been addressed in the discussion i.e do not introduce anything new in conclusion

MARK SCHEME FOR THIS LAB WILL BE POSTED ON THE WEBSITE biowithcc.

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