- Partially permeable membranes have holes in them. These holes are the size of just one water molecule.
- Water can pass through the membrane in both directions although if there is a higher concentration of water in the solution rather than the potato chip, the potato chip will receive water molecules and will increase in size.
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Some membranes in plant and animal cells allow only certain particles to pass through them. They are partially (or selectively) permeable.
Prediction
I predict that as the concentration of the sucrose solution decreases the mass of the potato chip will increase. I think this because a lower sucrose content would mean a higher water content and therefor as osmosis takes place the water in the solution will move from the solution to the potato chip and as a result increasing the mass of the potato chip.
I also predict that the concentration of the solution and the mass of the potato chip will be directly proportional to each other.
Variables
In this investigation I will change the concentration of the solution and I will be keeping the size of the potato and the temperature of the solution the same.
Equipment
Below is the apparatus that I will be using for my investigation.
- Cutting tile
- Small knife
- Measuring cylinder
- Distilled water
- sucrose
- Potatoes
Method
- Firstly I will cut five pieces of potato.
- Then I will peal the potatoes with the knife.
- After this I will measure and weigh them to ensure that they are equal.
- Subsequently I will put 40ml of my solution in each of the testubes.
Test tube one will have 10ml of distilled water and 30ml of sucrose.
Test tube two will have 20ml of distilled water and 20ml of sucrose.
Test tube three will have 30ml of distilled water and 10ml of sucrose.
Test tube four will have 40ml of distilled water and 0ml of sucrose.
Test tub five will have 0ml of distilled water and 40ml of sucrose.
- Next I will put 1 potato in each of the test tubes
- Finally I will seal the test tubes and place them in a rack for 15hours, after which I will measure the weights and lengths of each potato chip and then show my findings in a graph and table.
Fair test
To ensure that my investigation is conducted fairly I will be weighing each potato chip to ensure that all the chips are the same weight, I will also measure each potato chip to keep them the same size. Also I will be putting all my potatoes in the same place so that they are kept at the same temperature and receive the same amount of sunlight.
Safety
To ensure that my experiment is conducted safely I will wear goggles to protect my eyes from any possible hazards. I will also be using a small blunt knife so as that I do not injure myself.
