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Potato Osmosis. Aim: To establish the effect of osmosis on the volume of a potato cylinder.

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Introduction

Potato osmosis Aim: To establish the effect of osmosis on the volume of a potato cylinder. Hypothesis: I think that the rate of osmosis will have a minor effect on the volume of the potato cylinder. Apparatus/ material: * Ruler * Electronic weight * Different volumes of sucrose (0.1 , 0.2 , 0.3, 0.4 and 0.5) * Distilled water * Test tube * Cork borer * Knife * Stopper * Test tube rack * Filter papers Method: Using the cork borer and the knife, prepare a cylinder of potato, measure the length of this cylinder and make sure it is 12 mm and that the diameter is 10 mm. Now, cut the cylinder into six discs of approximately equal size, and place them on a filter paper. ...read more.

Middle

Cover the top of each test tube with a stopper and place the test tubes in the test tube rack. After 24 hours, remove the test tube and get rid of any surplus fluid inside them, then place the potato discs into in a filter paper and weight them using the same method used earlier. Record the new weights and draw a table comparing the initial and final weights of potato with each solution. Results: Initial mass (grams) Final mass (grams) Distilled water 2.3 2.65 0.1 sucrose solution 2.81 2.96 0.2 sucrose solution 2.99 3.15 0.3 sucrose solution 3.04 2.80 0.4 sucrose solution 3.04 2.52 0.5 sucrose solution 2.77 2.04 Discussion: The reason for dividing each cylinder into six discs is to increase the surface area and hence the rate of osmosis in the surface of the cylinder. ...read more.

Conclusion

Having done this experiment, I now know that the solution in the vacuole of the potato has less water potential the dilute water, its concentration is equivalent to almost 0.35 mol dm-3 sucrose solution, as shown by the graph. Evaluation: To make this experiment as fair as possible, I: 1. Made sure the all the experiments were made at room temperature. 2. Placed all the potatoes in their solutions for the same amount of time. 3. Covered each test tube to decrease the rate of evaporation which might increase the concentration of the sucrose solutions. 4. Cut cylinders of the same potato. But there were certain factors that I might have made the experiment less accurate, there are: 1. The filter paper that was weighted with the potato discs might have gained weight from the water in the surface of the discs. ?? ?? ?? ?? ...read more.

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