The investigation of Osmosis in Potato Chips.

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Priya Thakrar 10Y
Biology Coursework

The investigation of Osmosis in Potato Chips

Osmosis will occur across a semi-permeable membrane whenever there is a difference between the water concentrations on the two sides of the membrane, and when this happens to cells they will either become turgid if water flows into them, or plasmolysed if water flows out of them, and therefore changing their mass.


Aim: 

To investigate how changing concentration in a sugar solution affects the rate of osmosis in potato chips.

Prediction:

I predict that as potato chip is placed in a solution of high water concentration then the potato chips will increase in weight and if put in a low concentration then it will do the opposite.

If the concentration of a solution into which a potato chip of 2cm of a potato is placed is greater than a certain level the potato chip will contract, and if the concentration is less than that level it will expand. This can be seen in living cells.
The cell membrane in cells is semi-permeable and the vacuole contains a sugar/salt solution. So when a cell is placed in distilled water (high concentration of water), water will move across the semi-permeable membrane into the cell (lower concentration of water) by osmosis, making the cell swell. This cell is now
turgid. If this were done with potato cells the cells would increase in mass because of the extra water. If these potato cells were placed in a solution with a low water concentration, then the opposite would happen. Water would move out of the cell into the solution. In extreme cases the cell membrane breaks away from the cell wall and the cell is referred to as plasmolysed. The potato cells will have decreased in length, volume and mass.

The greater the concentration of water on the out side of the cell the greater the amount of water that enters the cell by osmosis. The smaller the concentration of water out side the cell the greater the amount of water that leaves the cell.

Pilimilary Experiment:

Aim:

To find our which way water molecules between tap water and a strong sugar solution.

Diagram:

A        Water diffuse out of ‘cell’        B         Water diffuses into of ‘cell’

This diagram shows the visking tubing, which is partially permeable membrane, and is always used to show the effects of osmosis. In pure water as shown in experiment B swells and becomes turgid as water enters by osmosis. However, in a strong sugar solution on (1 molar) water leaves the visking tubing by osmosis and it becomes flaccid.

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But what exactly is Osmosis?
Each cell is surrounded by a membrane, which has tiny holes in it. This membrane is partially permeable (just like the visking tubing) It allows small molecules to pass though but not larger molecules.

Osmosis is the movement of water for ma high concentration (or weak solution, on this case 1 molar water) to an area of low concentration (a strong solution, in this case 1 molar of sugar solution) through a partially preamble membrane. So, the water is moving both ways to even up the concentration. if there is more movement one way, it is ...

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