Osmosis in Potatoes

'Osmosis in Potatoes' Experiment

Apparatus

Test tubes

Test tube rack

Potato digging tool

Scales

Method

First, a tool to dig out cylinders of potato from a whole, raw potato was used to dig a cylinder for each test tube that contained either: 30ml distilled water, 30ml 10% sugar solution, 30ml 20% sugar solution, 30ml 30% sugar solution or 30ml 40% sugar solution. They were then each weighed separately and their masses were recorded. This was done twice to get the best results (so there were two test tube racks). Once there was one in each test tube, they were left for approximately 24 hours (15.00 - 13.00). At 13.00 the next day, the potato cylinders were removed from the test tubes and their masses were weighed and recorded.

Results

Start (15.00) Finish (13.00)

5 Solutions 1st chip mass 2nd chip mass 1st chip mass 2nd chip mass

Distilled water 5.74g 4.80g 6.64g 3.87g

10% sugar solution 5.84g 5.71g 5.37g 3.69g

20% sugar solution 4.84g 5.93g 3.39g 2.53g

30% sugar solution 4.69g 2.27g 2.53g 1.50g

40% sugar solution 6.24g 4.41g 2.09g 1.18g

Conclusion

The potato cylinder in the distilled water was the only one to gain in mass. This is because the potato became turgid as it soaked up the water, by osmosis. The others decreased in mass. This tells us that osmosis has already taken place in the potato in the distilled water. This is because if the concentration of the solution is higher than the concentration of the potato, it would contract (sugar solutions) and if the concentration is lower, it would expand (distilled water).