Investigating the Concentration of the Solutions Inside the Vacuole of a Potato Cell.

Osmosis Investigation

We are trying to find out what the concentration of the solutions is inside the vacuole of a potato cell.

We will investigate how the mass of the potato chips change in different sucrose solution concentrations.

We will use osmosis to do this.

I will be measuring and controlling many different variables, these include; -

The dependent Variable – Weight of potato chip

Independent Variable – Concentration of sucrose

Control Variables consist of; -

1. Temperature
2. Surface area of potato
3. Volume of sucrose solution
4. Same time for each potato chip submerged in solution
5. Potato chips all from same potato

The effects on the dependent variables all differ; here is how the main variables in my experiment work out.

Variable Effect on Dependent Variable
Surface area of potato chip The greater the surface area the more water it will be able to absorb
Same chip from the same potato The genetic make-up will be the same and therefore the partly permemble membrane will be similar
Time left in the solution The longer spent in solution the more that is absorbed
Coating on the potato chips If not rinsed off and dried after a certain period of time the chips will form a coat of sugar thus decreasing surface area

Quantitative prediction

I predict that the effect of changing the sucrose concentration will be that as the concentration of the sucrose solution increases, first of all the mass of the chip will increase, and then the change in mass will gradually decrease until mass is lost and this mass loss will gradually increase in amount.

Because when the sucrose concentration is low, the concentration of water outside the cells of the potato chips will be greater than that inside, and therefore water will osmosis into the cells of the chip which will gain mass. As the concentration of sucrose increases the concentration of water outside the call will eventually become less than inside the