The aim of this experiment is to investigate how changing the concentration of a solution will affect the rate of osmosis. I intend to use different glucose solutions as my variable and potato cylinders as my living organism.

COURSEWORK

Introduction:

Hypothesis:

I predict that the higher the glucose concentration is, the lesser the potato would weigh. This is because the potato contains more water than the glucose solution therefore it leaves the potato and goes into the solution in an attempt to even up the concentration on each side of the membrane.

Biological Knowledge:

Osmosis is the movement of water molecules across a partially permeable membrane from a region of high water concentration to a region of low water concentration. A partially permeable membrane is one with very small holes. They are so small they can only allow water molecules to pass through unlike bigger molecules such as glucose. An example of a partially permeable membrane is a Visking Tube. The water molecules actually pass both ways through the membrane. Because there are more on one side than the other there’s a steady net flow into the region with fewer water molecules for example into a stronger solution (in this case glucose). This causes the region with a lot of glucose to fill up with water. The water acts like it’s trying to dilute it, so as to ‘even up’ the concentration on either side of the membrane.

Water Sugar Solution

Osmosis can make plant cells swell up if they’re surrounded by weak solution causing them to become turgid. This is useful for providing support to green plant tissue and for opening stomatal guard cells.

Animal cells don’t have a cell wall and can easily burst if put into pure water because they take in so mush water by osmosis.

Apparatus:

I will need the following:-