Name:
Date:
FORM 4 BIOLOGY
Topic: Movement of substances in and out of cells Osmosis
Title: Osmosis in Potato Tissue
Aim: To observe the effect of different concentrations of salt solutions on potato.
Apparatus & Materials:
Method:
1. Use a knife cut 8 cylinders of potato, taking care with fingers.
2. Trim the potato cylinders to the same length.
3. Measure the length of each cylinder and test its firmness by gently bending it.
4. Label cups: water with no salt(A), 1 teaspoon of salt(B), 3 teaspoons of salt(C) and
6 teaspoons of salt (D).
5. Add the required quantity of salt to each cup and then place 100 ml of water into
each cup. Stir to ensure all of salt dissolves.
6. Place two (2) potato cylinders in each solution, leave for 30 minutes.
7. After 30 minutes remove the cylinder and blot potato dry, then measure the length
and firmness of the potato cylinder.
Diagram of apparatus used to show effect of different concentrations of salt solutions
on potato cylinders
Results: Table to show effect of different concentrations of salt solutions on potato
cylinders
Before Experiment
Solution
Water (A)
1teaspoon of
salt (B)
3 teaspoons of
salt (C)
6 teaspoons of
salt (D)
Firmness
Length 1
(cm)
Length 2
(cm)
After experiment
Average
Firmness
Length 1
(cm)
Length 2
(cm)
Average
Calculations:
% change in length = (change in length / starting length) X 100
Solution
Water (A)
1teaspoon of
salt (B)
3 teaspoons of
salt (C)
6 teaspoons of
salt (D)
Discussion:
Conclusion:
change in % change in
length (cm)
length