Osmosis Start

Investigate osmosis between potato tissue and sugar solutions.

Aim: To investigate the effect of varying concentration of a certain sugar solution on the amount of osmotic activity between the solution and a potato core of a given size 10mm

Hypothesis: Osmosis is defined as the net movement of water or any other solutions molecules from a region in which they are highly concentrated to a region in which they are less concentrated. This movement must take place across a partially permeable membrane such as a cell wall, which lets smaller molecules such as water through but does not allow bigger molecules to pass through. The molecules will continue to diffuse until the area in which the molecules are found reaches a state of equilibrium, meaning that the molecules are randomly distributed throughout an object, with no area having a higher or lower concentration than any other.

Predictions: For this particular investigation I think that the lower the concentration of the sugar solution in the test tube the larger the mass of the potato will be. This is because the water molecules pass from a high concentration, i.e. in the water itself, to a low concentration, i.e. in the potato chip. Therefore, the chips in higher water concentrations will have a larger mass than in higher sugar concentrations.

Planning: I am going to experiment the effects of osmosis in potato cells using varying of sugar solution. The samples will be placed in 3 test tubes for every different sugar solution. The samples will then be left in the solution for 24 hours, taken out of the solution and measured in length.

Care will need to be taken when cutting the samples to length and acquiring the samples from the potato because a scalpel will be used to cut the samples to an exact length and an apple core borer will be used to obtain the samples. Both of these items used are very sharp.

The molarities used for the sugar solution will be 0% (water), 4%, 8%, 12%, 16%, 20%. 3 sets of results will be taken for each percentage to make sure the evidence gathered is scientifically correct. Care will have to be taken not to spill any of the sugar solutions. The control for the experiment will be the 3 sample in 0% of sugar solution (Water). The variables will be all the other solutions 4%, 8%, 12%, 16%, 20%. The length of the samples and type of potato must be kept

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