In this experiment I am going to investigate how different

In this experiment I am going to investigate how different

concentrations of sucrose solution can alter the process of

osmosis on a potato chip, and in what way it does this.

Osmosis

Aim:

In this experiment I am going to investigate how different

concentrations of sucrose solution can alter the process of osmosis on

a potato chip, and in what way it does this.

Prediction:

I predict that due to osmosis and diffusion when there is a pure water

solution the potato chip will swell as it absorbs the water to

equalise.

However, if there is a mild/rich sucrose solution on the out side of

the potato chip it will shrink as water is sucked out of them by the

process of osmosis.

Research:

If substance has a semi-permeable wall with holes small enough to

allow small water molecules to pass through but not big enough to

allow greater sized molecules such as sucrose molecules.

Osmosis is a type of diffusion; when there is a higher concentration

of a certain type of molecule on one side of a semi-permeable

membrane, a process of diffusion (osmosis) tries to level out the

balance of the highly concentrated solution to lower the concentration

until it is equal on both sides.

For example:

Some water is placed in a science beaker (A), and then some 20% sucrose

80% water solution is placed in a piece of visking tubing (D).

When this is placed in the water contained in the beaker (A) there

becomes an imbalance of concentrations either side of the

semi-permeable membrane, on the inside of the membrane there is a

stronger concentration or ratio of sucrose against water than there is

in the outside.

Therefore the sucrose would be required to equalise, by 10% or so

moving to the outside of the tubing, there comes the problem.

Due to the size of the small holes in the visking tubing, big

molecules, such as sugar, C6H12O6 that is 24 atoms big, cannot pass

through, however small ones such as water, H2O with three atoms to a

molecule, can.

Therefore, since there is no way of moving the sugar, the best thing

to do is to add more water to the inside of the visking tubing. By

osmosis and diffusion, the smaller molecules move into the visking

tubing whilst the bigger sugar molecules stay.

That is osmosis. Plants also use this method to provide nutrients and

various chemicals to their cells.

Equipment:

For my experiment I will need a total of:

Four test tubes; one potato; 2%, 5%, 10%, 20% sucrose and water

solution; one knife; one marble cutting plate; aluminium foil; four

sticky labels.

Method:

1. Cut the potato into equal strips and weigh them.