Measuring The Rate Of Osmosis In Potato Cells

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Measuring The Rate Of Osmosis In Potato Cells

Skill Area P.

Osmosis is defined as free water molecules diffusing from a high

concentration to a low concentration through a semi-permeable

membrane.

Variables - The rate of osmosis effected by many different living

things, temperature of the solutions, surface area over which it can

occur, Volume of solution, Volume of potato, distance through which

the free water molecules have to pass and finally the difference in

concentration of the solutions. This final factor is the one that we

are going to test during the experiment.

The temperature increase causes the cells to expand so the whole

potato expands. Different volumes of potatoes at different

temperatures could be measured, however trying to measure the

temperature of a potato effectively without causing defects in other

results would be quite hard with the equipment we are using.

The surface area over which the osmosis occurs can change the speed at

which it happens dramatically. The larger the surface area between the

two solutions the faster osmosis will happen. This is due to more of

each solution will be in contact with the membrane at one moment. This

means that a larger amount of the free water molecules in the solution

can move across the membrane at the same time therefore making the

process happen much faster. Due to this it is vital that the surface

area of the potato in contact with the outside solution is kept

constant. This will be done by the potato being cut in exactly the

same shape and size.

The water affects the osmosis and the rate of osmosis. The variation

of osmosis could differ whether it's a high concentration or a low

one. The concentration of the solution is measured in Molar; the

amount of Molar will also affect the solutions concentration.

The thickness of the membrane over which the osmosis is happening also

affects the rate of osmosis, because the free water molecules need

more energy to pass through the membrane the thicker it is fewer

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