Experiment: Testing for osmosis in living plants

Materials: potatoes, knife or blade, distilled water, sugar or salt, three containers,weighing balance.

Method

Prepare three pieces of peeled potato. Each block must be the same size about 5cm x 1cm x 1cm in size.

Place them in distilled water until they are required.

Prepare three solutions using either salt or sugar and place it into three different containers as follows:

A distilled water.

B 5% sugar/salt solution

C 10% sugar/salt solution

The 5% solution is made by dissolving 5g of sugar in 95g of distilled water.

The 10% solution is made by dissolving 10g of sugar in 90g of distilled water.

Record the size of each potato piece.

Add each piece to each solution and leave them for a day.

Measure and record the size of each piece of potato.

Results

There is an increase in size in the size of the potato piece that was placed in distilled water.

There is no discernible change in size in the potato piece that was placed in the 5% solution.

The piece in the 10% sugar solution experiences the largest shrinkage.

Explanation

There is more water concentration outside the potato piece than inside it resulting in water entering the piece via the osmosis process.

There is more or less equal concentration of water without and within the potato piece resulting in negligible change in size to no change in size.

There is less water concentration of water outside the potato piece when compared to the inside of the plant resulting water moving out of the potato piece via osmosis resulting in the piece shrinking in size.

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