Osmosis In A Potato

Osmosis In A Potato

Intro:

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My biology coursework is based round the osmosis process that takes

place in potatoes. Osmosis is the intake of a salt solution through a

selectively permeable membrane. The strength of a salt solution can

have a dramatic difference on the amount the potato can take in, and

how it reacts.

Here is an example of a selectively permeable membrane…

Salt Solution

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Strong

Weak

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Strong

Weak

Salt Solution

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Variables:

An fundamental necessity in my biology experiment is to decide which

variable I am going to use and modify. A variable is an aspect of the

experiment which can be modified in order to change the outcome of the

entire osmosis experiment. Below are the variables I have available

* Temperature

* Solution Strength

* Size Of Potato

* Weight Of Potato

After a lot of careful deliberation I have decided to use the solution

strength as my variable. I chose this because it enables me to witness

the effect different strengths of solution have on osmosis.

Method:

To carry out my experiment successfully I will need to stick to the

diagram below….

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Firstly, I will take 6 test tubes with different strength salt

solutions and add them to a test tube rack. I will then cut up a

potato and measure them to make sure they are the required size, for

this experiment I have chosen 1.0cm. I will then add two measurements

of potato into each test tube. The test tube will then be left over

night in a fuming cupboard, and results will be taken the next

morning.

Fair Test:

To make sure my experiment is fair I will stand by the following

guidelines…

* Use the same sized test tube.

* Make sure each strength is measured exactly.

* Make sure each piece of potato is exactly the same size as the next.