This can be seen in living cells. The cell membrane in cells is semi-permeable and the vacuole contains a sugar/salt solution. So when a cell is placed in (high water concentration) water will move across the semi-permeable membrane into the cell (lower water concentration) by osmosis, making the cell swell. This cell is now referred to as turgid. If done with potato cells the cells would increase in length amount and mass because of the extra water. If these potato cells were placed in a solution with a low water concentration, then the opposite would happen.
The greater the concentration of water in the external solution the greater the amount of water that enters the cell by osmosis. The smaller the concentration of water in the external solution the greater the amount of water that leaves the cell.
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Planning:
The potato, cut up into pieces, In the water, I believe that the water is more concentrated in the potato, and therefore the water should transfer from the water to the potato, making the potato bigger in size, and heavier in weight. The potato, being surrounded by a weak solution, will be most likely to swell up and become turgid, taking in all the water it can possibly take in.
With the potato in 2 grams of sugar solution, I don’t think there will be much change in the weight of the potato. This is because there isn’t much difference between the two substances. I believe that the weight and the size of the potato won’t be altered much.
The 4-gram solution of sugar, similar to the 2 grams of sugar, compared to the potato, both substances have very close concentration. And that is why I am predicting that the weight of the potato in this experiment should be decreased by only a little bit.
The 6-gram solution of sugar, I think, should make a big difference now, noting that it should be a large difference between the two concentrations. And therefore the weight should decrease, at least noticeable for you to notice. Also anything above that you will notice.
The difference between the water concentration in the potato and the 8-gram solution of sugar is big, and the water in the potato should be transferred from the potato, through the permeable membrane, to the solution nearby the potato. As a result, I am sure that the weight of the potato will increase largely.
My guess in this experiment is that, due to the difference in the water concentrations of the two substances, I believe that the weight of the potato will start decreasing when it is tested on 2 grams of sugar solution and greater.
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Apparatus I will need:
· Borer
· Water,
· Measuring cylinder,
· Potato,
· 2g, 4g, 6g, 8g 10g of sugar solutions,
· Scales,
· Beakers,
· Ruler,
. Paper towels
I plan to carry out this experiment by using all the fair testing measures to give me the most reliable and most accurate set of results.
I plan to have a range of sugar solutions prepared with concentrations from 1g to 10g, in intervals of 2g, I will be taking 5 results to explain the effects of the potato on osmosis.
Then sections of potato will be cut using a borer to equal lengths (? cm) keeping the surface area the same. I will then measure each bit of potato using a measuring scale, measured in grams. I will then add 50ml of water using a measuring cylinder into the beakers, giving me a total of 5 beakers, and then adding the amount of sugar for each beaker according to the amount of sugar concentrate I want, and labelling each solution reading 2g, 4g, 6g, 8g, 10g…etc…. The pieces then go into the different beakers. Once the potato pieces have been left in the different solutions they will have to be left there for 24 hours. Then the potato pieces will be removed from the different beakers, and surface solution on the potato will be removed using paper towels. I will then measure the potatoes again, recording its change in mass by weighing them. I will then be taking the readings of each concentration. As it is difficult to get the cut potato pieces to the same mass it was decided that I would use a percentage change in mass, which will be used to compare the data in the results, as, this would be far more accurate. I will do this by taking the difference in mass; divide it by the mass before of he potato and multiplying it by 100.
