Investigation into factors that affect Osmosis in potatoes.

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Investigation into factors that affect Osmosis in potatoes

I will investigate how different concentrations of sucrose affect potato in terms of turgidity. The sucrose will be in varying concentrations compared to water.

I hypothesise that the higher the concentration of sucrose around the potato, the more mass the potato will lose. I believe that this will happen as the potato will try to lose water to equalise the concentration of the sucrose compared to water, this is the process of osmosis. This happens through the pores on the selectively permeable membrane on the potato, which allows water through it but not sucrose.

To measure the effect of osmosis with sucrose on potatoes, I will measure percentage change in both length and mass, using balances and measuring implements. I will measure weight to 2 decimal places, and length to the nearest millimetre. I will follow normal laboratory procedure, and will take special precautions when using scalpels and borers.

I will cut the cylindrical pieces of potato to the same diameter which is 5mm, by using a cork borer and to the same length (4cm), by using a scalpel. I will put the piece of potato into a boiling tube, and I will put varying concentrations of sucrose in with it. I will put 10ml of sucrose with 0ml of water, then 8ml Sucrose and 2ml water, then 6ml sucrose with 4ml water, then 4ml sucrose with 6ml water, then 2ml sucrose with 8ml of water and 0ml sucrose with 10ml of water. I will leave the boiling tubes overnight, and will then remove, measure length and weigh each piece of potato. I will take the percentage change of each piece of potato by:

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Change in length x100

Original length

Change in mass x100

Original mass

Although if the pieces of potato do not have enough time in the boiling tubes to complete the process of osmosis, the results will not be accurate. In my preliminary experiment I found that the potato did have enough time to complete the process, so the results should be accurate.

Variables involved are: length and diameter of pieces (this will be kept the same), amount of solution (same), temperature (room temperature), Time (this will be kept the same), type of potato (same), size of potato (same) and ...

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