Biology Controlled Assessment - osmosis in potatoes

this is the low control part of my GCSE Biology Controlled assessment

My experiment was investigating how the mass of the  potato cylinders changed as they were left in different solutions of NaCl. 

Hope it helps & dont forget to rate ;)

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  • Created by: Rita
  • Created on: 01-04-13 17:07

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Biology Controlled Assessment

Introduction

Osmosis is the diffusion of water from a high concentration to a low concentration
through a semi-permeable membrane.
This process does not require energy and is known as passive transport, it works
through pressure to reach equilibrium, i.e. the same concentration on both sides.

There are…

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For my experiment I choose solute concentration as my independent variable,
because it's the easiest variable from which to produce reliable, accurate and
reproducible results. I decided not to use temperature as my independent variable
because I believe that it would be more difficult to control and measure than osmotic…

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Test tube rack ­ here isn't a better alternative for the same purpose. My
only principle was that it is easier to keep track of the potatoes when they are
in a rack
18 Test tubes ­ there isn't much difference in the equipment that can be
used to hold…

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3% 60 40
2% 40 60
1% 20 80
0% 0 100


After all the solutions were mixed we labeled them and put them aside. We then
began cutting the potato cylinders. We first set out the cutting tile, onto which we put
the potato. We cut the potato using…

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Strategy ­ S(c)

Before doing our preliminary work, within our group we agreed on a general technique
that we were going to use to do the experiment and use the preliminary work to check
whether the method was good or not and how it could have been improved. In our…

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concentration Before After
( % ) ( g ) ( g )
5 1.72 1.23
4 1.65 1.28
3 1.75 1.34
2.5 1.62 1.36
2 1.73 1.42
1.5 1.75 1.74
1 1.65 1.70
0.5 1.76 1.81
Distilled water 1.63 1.99

















As it can be seen from the results we began…

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Range used: - from 0% NaCl concentration (i.e. distilled water) to 5% NaCl
concentration
Change in mass measured: - every 1.0 NaCl concentration
Time potato cuttings were left in the solution: - 3 hours
Size of potato cutting: - size 3 core borer cylinder

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