An Investigation into the process of Osmosis

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Paul Scanlon 26/1/2002

BIOLOGY SCIENCE COURSEWORK:

"An Investigation into the process of Osmosis."

Situation:

"A chip shop owner wants to pre-prepare chips and soak them overnight without affecting their size. He has noticed that their size after soaking depends on the concentration of the glucose solution they have been left in."

Aim:

Therefore, my aim in this investigation is to find out the exact glucose concentration of a potato to help solve this situation. By doing this I should be able to determine the concentration of the potatoes themselves.

Planning:

Before actually planning the experiment, I will do some research to find out about osmosis, and matters related to it, so that I can make my predictions. This would leave way for me to figure out a way to make this investigation fair and safe.

Planning ahead would help me find out how to do what and when to do it, which in turn should lead me to a set of good reliable results at the end of the experiment.

Factors affecting the investigation:

At this point in time, I cannot foresee many factors that could affect my experiment. But, there are some:

* As there are no two identical potatoes anywhere in the world, it would be hard to try to equal the glucose concentration of the two chips taken from different potatoes.

Therefore, I shall take all my chips from the same potato and hopefully, the single potato should have a glucose concentration equally throughout it.

* Different temperatures may affect my experiment. If I was to perform this experiment in a high temperature, then the rate of evaporation would increase and in turn, this would cause the concentration and amount of glucose solution to differ. If I were to perform this experiment in cooler conditions, then the rate would slow down more. Different temperatures will affect the rate of osmosis. The reason for this is that if there is a high temperature and some of the water is evaporated, amount of water being evaporated from each solution will vary because of the molar of the solution. This in turn will send my whole experiment wrong and give me a false set of results making my experiment a complete failure.

There fore I shall keep the temperatures constant throughout my experiment. I will do this by keeping everything at room temperature. I can check this throughout the experiment by putting a thermometer in the solution. I shall use a different one in each solution so not to mix them all up and

contaminate the different molar solutions.

Fair testing will play a big part in my experiment, as it should in everyone's. If my experiment isn't a fair test, I will be obtaining the wrong results, which could lead me to the wrong conclusions.

First of all, and most importantly, I will have to get the measurements and the weights of the solutions and the potatoes as exact, and as accurate as possible. I will try and get the measurements of the potatoes as accurate as possible for every single potato, evenly cutting the potato pieces, and making a record of the length to the nearest millimetre. I will be using a very sensitive balance so that I can get the best readings possible.
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But I believe one of the most important steps in the fair testing is to make sure that the potato is fully covered by the solution. This is because the potato should be fully submerged, by having total contact with the solution. This would give the potato complete contact with the solution and make the test fair because both potatoes then have 100% of the surface area in contact with the solution.

When using the balance, I will make sure that the balance is reading zero with the bowl on top before I put the 3 potatoes ...

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