An Investigation to Demonstrate Osmosis Using a Potato

An Investigation to Demonstrate Osmosis Using a Potato

Aim

I am going to investigate osmosis when potato is placed in different

concentrations of sucrose. I am aiming to witness osmosis in 6

different concentrations of sucrose. I will use 6 varying

concentrations so that I have a wider spread to compare the results,

and check that I don’t have any anomalies.

Prediction

Osmosis is the process of diffusion of water molecules from a weaker

solution into a stronger solution, through a semi permeable membrane.

The tiny pores in the membrane of the potatoes will allow the water

molecules to go in and out of the potato cell, depending on the

concentration gradient between the potato and the sucrose solution. If

the water concentration is lower in the potato than in the sucrose

solution, then water will pass from the sucrose solution into the

potato, and it will gain weight. If there is a higher concentration of

water in the potato, then the water will go out of the potato and into

the sucrose solution, as osmosis is the movement of water molecules

from a region of high concentration to a region of low concentration,

through a semi permeable membrane. So, I predict that the higher the

concentration of sucrose, the lower the weight of the potato as water

from the potato diffuses into the sucrose solution.

Predicted graph of results:

[IMAGE]

Apparatus

* 6 test tubes

* 6 different concentrations of sucrose solutions

* Potato

* Potato cutter/core

* Digital measuring scales

* Measuring cylinders

* Knife

* Test tube racks

* Coloured felt pens

* Tissue paper

Method

I will need 3 pieces of potato in each tube. As there are 6 tubes I

will have to calculate how many pieces I will need altogether. I think

this would be a suitable calculation: 6x3=18.