The Effect of Solute Concentration on Osmosis in Potatoes.

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Martina Oganesyan
Title of investigation: The effect of solute concentration on osmosis in potatoes. Research question: What is the solute concentration of a potato? Hypothesis:
Osmosis is the movement of water across the membrane from an area of high concentration to an area of low concentration. The osmosis continues until the solute concentrations are equal in both areas. In this experiment, we put pieces of potatoes into test tubes with sugar solutions of different concentrations and leave them there over night. It was done in order to compare the initial mass of the pieces and the ones after being placed into the solute concentration. Pieces which were placed into a hypotonic (lower) concentration of solute should increase in mass, those in hypertonic (higher) concentration should decrease in mass and the ones put into an isotonic concentration (same) should stay the same before and after. All those changes will take place because of osmosis. Dependent variables: change in mass of pieces of potatoes.

Independent variables: solutions sucrose concentrations.
Controlled variables: amount of time in the solutions; surface area of the potato segments; diameter of the test tubes; temperature. Material:
* 10 same size potato cubes
* 10 test tubes
* Sucrose (C12H22O11)
* scalpel
* distilled water
* balance (±0.05)
* test tube holder
* temperature probe (±0.01)
* graduated pipette (10ml±0.75)
* Erlenmeyer flask (1L ± 25ml)
* Thermometer

Take a potato and cut out 10 cubes using a scalpel, which are equal in size. After, 10 test tubes have to be selected for a different sugar solution concentration each, starting from 0.1 mol/l until 1.0 mol/l. First make a solution of 1mol/l using powdered sucrose (the mass needed to do so can be found using the formula n=m/M and weighed with a balance. Place the solutions into test tubes and fill with distilled water until the total volume of solute on in each test tube...
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