RP 3 - Osmosis

Created by

mona <3

Cards (7)

(3) Osmosis practical aim:
Immerse plant tissue in a range of concentrations of salt or sugar solution, find the change in length or mass of the plant tissue to investigate the movement of water by osmosis into or out of the plant tissue.
(3) Osmosis practical equipment:
● Plant tissue eg. potato
● A cork borer
● A ruler
● A measuring cylinder
● Labels
● Boiling tubes
● A test tube rack
● Paper towels
● A sharp knife
● A while tile
● A range of salt or sugar solutions
● Distilled water
● A top-pan balance
(3) Osmosis practical method 1-7:
Use a cork borer to cut 5 potato cylinders.
Trim the cylinders using a sharp knife and a ruler to the same length (about 3 cm).
Accurately measure and record the length and mass of each cylinder.
Measure 10 cm3 of the 1.0M sugar solution and transfer to the first boiling tube and label.
Repeat step 4 for other concentrations of the solution and distilled water.
Add one potato cylinder (of known mass and length) to each boiling tube.
Prepare a table as seen below.
(3) Osmosis practical method 8-11:
8. Add one potato cylinder to each boiling tube, making sure the length and mass of each cylinder is known.
9. Leave the cylinders in the boiling tubes overnight in a test tube rack.
10. Remove the cylinders from the boiling tubes and carefully blot them dry with paper towels.
11. Measure the length and mass of each cylinder and record your measurements in the table. Calculate the percentage changes for each cylinder.
(3) Osmosis practical method 12-13:

12. Plot a graph of change in mass (in g) against the concentration of sugar solution.
13. Plot a graph of change in length (in mm) against the concentration of sugar solution.
(3) Osmosis practical sources of error:
Discs taken from different parts of the potato may have different water potentials. Potato discs may have different surface areas which affect the rate of osmosis.
(3) Osmosis practical risk assessment:
Take care when handling cork borer and sharp knife.