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How much does osmosis occur when a potato slice is place in a test tube with a sugar and water solution?

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Introduction

Coursework Biology investigation How much does osmosis occur when a potato slice is place in a test tube with a sugar and water solution? Osmosis Osmosis is basically diffusion but it is a special kind. This occurs when a membrane has tiny holes in it that lets water molecules pass through but stops larger molecules like sugar. This sort of membrane is called a semi-permeable. Osmosis in a potato When osmosis occurs in the potato the water should move from one side to another (form inside the potato slice to the solution outside or the other way round) moving through the semi-permeable membrane coating the potato cells. Aim I am trying to find the extent of osmosis when a potato is put into a sugar solution and if the amount of osmosis occurring changes if the solution has a high or low concentration of sugar. Prediction Inside the potato is water and sugar molecules when we drop a slice of potato into the test tube with the sugar and water solution we will try to see if osmosis occurs. ...read more.

Middle

Scalpel Bungs Protective gear Test tube rack Diagram Method 1. First we will gather our apparatus and set it up as shown below 2. Secondly we will use the cork borer to cut long slices out of the potato. Then, using the scalpel and the balance, cut the potato so it weighs exactly 0.50g and measures exactly 7mm in diameter and 10mm in height. 3. We will then get the test tube rack and put in 5 test tubes and label them with all the different concentrations. Then put 20cm� of the corresponding solution in the test tube. 4. After this we will put three slices of the potato into each test tube and put a bung on the top and leave it for 3 days. 5. After 3 days we will take the bungs of the tops and take the pieces of potato out of the solution and dab any excess solution from the outside. We will then weight each one and record the results in a table. Results Concentration (m) Weight after osmosis (g) AVE Percentage increases 1 2 3 0.0 0.59 0.56 0.65 0.60 20% 0.1 0.58 0.58 0.62 0.59 18% 0.2 0.54 0.56 ...read more.

Conclusion

I would also use a balance to three decimal places. Also I would measure my potato slices out more accurately. This would give me a more accurate reading as to how much osmosis is taking place. During this experiment I found out that the extent of osmosis is much larger than I though as I felt that it would be hard for the particles to pass through what looked to me like a membrane that was totally waterproof I would improve my investigation by making it more accurate. I would use visking tubing in a broad range of concentrations and a computer to read the weight change over a period so the computer could show me when osmosis is occurring the most. I would use visking tubing as it can hold larger amounts of solution and so more osmosis would take place and so a more obvious weight change would occur. As an extension to this, I would also measure the length and depth of the pieces of potato so then I would see if there was any size change as well as weight change. I could also use different potatoes to see if there is a difference in concentration between potatoes. ...read more.

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