Investigation into Osmosis, in Potato Cylinder

In the preliminary experiment I saw that the cells of the potato were turning plasmolysed and when the water was added the potato cells were becoming turgid. However we did measure the cylinders of potato and made a note of how much concentration was going into the boiling tubes. The water molecules are smaller than most solute molecules which allow them to diffuse through the very small molecules.

Preliminary Test: This test was a brief experiment to allow me to see what happens to the potato cylinders in certain concentrations. This test was also to see what accurate type of range I could use and what could be improved on for my actual test. This is my table and what I obtained from it as well as the actual observation of the potato.

The high lighted squares shows that one length increased by 1mm and the other decreased by 1mm. This made me chose my accurate range for this work, by changing the concentration amount accurately to 0.0M - 0.5M.

Fair Test:

Apparatus:

• Potato - For finding the concentration in the cells
• Core Borer - For creating the cylinders
• Sucrose - For mixing it with the distilled water to create various strengths of concentration
• Distilled Water - Mixing it with the sucrose to make the varied strengths of concentration.
• Boiling tubes - To hold in the cylinders and concentration
• Boiling tube rack - TO hold the boiling tube
• Scalpel - To cut the potato lengths 3cm for all of them

Diagram:

Method:

1. Using the core borer, we cored out 15 cylinders of potato with the width of 75mm wide. The lengths were then cut down to 3cm long, using the same ruler to make it fair.
2. The concentrate was measured out in the same measuring cylinder of 10ml and was then poured into the 15 boiling tubes, we did this by molarity using sucrose and distilled water. We used the accurate ranges from the preliminary tests for making up our concentrate(as we know the more of the sucrose, more the cells will become plasmolysed).
3. The cylinders were then placed into the solution in the boiling tube in 10 seconds as it was impossible for them to be put into the tube at the same time.
4. The tubes were left for 20hrs and 40mins. We left the tubes un covered as the room temperature would probably stay the same and pressure, but these factors would maybe affect the osmosis, but the size, volume and surface area would be the same.
5. When it comes to check on the cylinder lengths, using the same ruler to cut them down to size was also used to measure the length.