Osmosis (Its A Bit Poo) Essay, Research Paper

Plan

In my experiment, I plan to find out whether the concentration of sugar in water affects how much water will go in to a potato chip. I will do this by having twelve test tubes three with one molar of sugar solution, three with ? molar sugar solution, three with ? molar sugar solution and three with zero molar sugar solution. I will do three of each so I can take an average from the results.

Prediction

For the investigation I think that the lower the concentration of sugar in the test tube the larger mass the potato chip will be. I think this because I know that Osmosis is the movement of water molecules across a partially permeable membrane from an area of high water concentration to an area of low water concentration. Therefore the water molecules pass from a high concentration (in the water itself) to a low concentration (in the potato chip). Therefore, the chips in higher water concentrations will have a larger mass than in higher sugar concentrations.

Diagram For Prediction

This is a diagram for what I predict will happen in the experiment. If the potato is in one Molar solution then the increase in mass due to osmosis will be little, as there is more sugar than water in the solution. If it is in 0.5 Molar solution, it should increase a little. If it is in pure water then the increase will be quite a lot, as there are many water molecules in water, therefore due to osmosis its mass will increase more that the other two experiments.

Fair Test

In the investigation, I will make it a fair test by keeping the following things the same:

1. Volume of solution ? 20ml

2. Same size boiling tube

3. Same type of potato

4. Temperature ? Room Temperature

5. Same sugar solution

6. Same size potato borer

7. Time left for ? 48hrs

8. Size of potato chip ? 20mm

For all of these criteria, having them not uniform in all of the tests would mean it would not be a fair test. For instance if I had a longer potato the surface area would be bigger and there would be more space for osmosis to occur.

Apparatus

To do this test I will need ?

1. Twelve test tubes

2. Sugar solution

3. Water

4. Twelve potato chips

5. Size 5 borer

6. Ruler

7. Two test tube racks

8. A Knife

Diagram

These are diagrams of how the apparatus is used. This first one is about boring the holes in the potato

This one is the potato chip in the water solution.

Method

1. Take about two or three potatoes and bore twelve potato cylinders out of them using borer size 5.

2. Cut the potato cylinders to 20mm, then set aside.

3. Collect twelve test tubes and put in test tube racks.

4. Measure 20, 10 and 15ml of water three times (3 x 20, 3 x 10 and 3 x 15ml water) then

5. Measure 20, 10 and 5ml of sugar solution three times (3 x 20 3 x 10 and 3 x 5ml sugar solution)

6. Mix these in this order, 20ml water in three test tubes. Three test tubes of 10ml water + 10ml sugar solution. Three test tubes of 15ml water and 5ml sugar solution. Finally three test tubes of 20ml sugar solution.

7. Attempt to put all potato chips in at the same time.

8. Leave for 48hrs.

9. Come back in 48hrs time and take all the potato chips out of the test tubes.

10. Roll them carefully on paper towels or other absorbent material to remove excess water.

11. Weigh each chip individually and record the measurement.

Results

Molar Mass at start Mass at finish Difference Increase in %

1.00 1.68 1.22 -0.46 -27.38

0.50 1.68 1.36 -0.32 -19.05

0.00 1.68 2.20 0.52 30.95

1.00 1.68 1.22 -0.46 -27.38

0.50 1.68 1.38 -0.30 -17.86

0.00 1.68 1.95 0.27 16.07

1.00 1.68 1.21 -0.47 -27.98

0.50 1.68 1.33 -0.35 -20.83

0.00 1.68 1.90 0.22 13.10

Graphs

See attached sheets.

Conclusion

My results show that the mass of the potato in the experiment with one molar of sugar solution decreased by about -27.68 % which means Osmosis must have occurred because the water leaving the potato?s cells into the sugar solution decreased the mass as the sugar molecules can?t get into the potato as its molecules are too big.

The potato that was in 0.5 molar sugar solution decreased in mass by -19.25%. Looking at the graphs you will notice that the graphs show a positive correlation. My results agree with my prediction in the sense that they are showing the same thing that I had predicted. Which was, that the potato chip would increase in mass when it was put into pure water and would decrease in mass when put into pure sugar solution.

Evaluation

The method I used was reliable. There were not any anomalous results; this can be seen on the graph as all the points on the graph correlate well. If I could do this investigation again, I would have repeated the investigation five times because if you do an experiment more times you get a better average. I could have investigated a wider range of variables (i.e. 1, ?, ?, 1/8, 1/16, 1/32) this would show better the relationship between sugar solution concentration and the amount of osmosis occurring.

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