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Effect Of osmosis on the size of potato rod.

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Introduction

Name : Maged Shereen Kamel Ibrahim Class : 4/8 Activity : B2.09 Dated : 10-4-2003 Coursework Assignment Effect Of osmosis on the size of potato rod Potato and osmosis investigation I. (PLANNING( Introduction Osmosis is defined as the net movement of water molecules from a region in which they are highly concentrated to a region in which they are less concentrated. This movement must take place across a partially permeable membrane such as a cell wall, which lets smaller molecules such as water molecules through but does not allow bigger molecules to pass through. The molecules will continue to diffuse until the area in which the molecules are found reaches a state of equilibrium, meaning that the molecules are randomly distributed throughout an object, with no area having a higher or lower concentration than any other. 1- The Aim of work To investigate the effect of varying concentration of a certain sugar solution on the amount of osmotic activity between the solution and a potato chip of a given size. 2- Used Equipments ? Test tubes (5 pieces) ? Syringe (to measure the amount of the solution used) ? Ruler (to measure the length of the potato chlip) ? Rack (to hold the test tubes) ? Stopwatch (to measure the time) ? Filter papers (to dry the potato chlips between) ...read more.

Middle

I have chosen to vary the concentration of the sugar solution. This will give me a vary varied set of results from which I hope to make a decent conclusion. If any of the non-variables below are not kept constant it would mean it would not be a fair test. For instance if one of the potato chips was 1cm longer the surface area of the chip would be larger and there would therefore be more space for osmosis to occur. 4- Precision For accurate results, I will not carry the potato chlip with your hand, I will Leave the test tubes for about 30 minutes before puting the potato chlip in order to have the same initial temperature (room temperature), I will be carful not to hold the test tubes with your hands during the experiment to avoid heat transfer, The stopwatch must be started at the exact time as we put the potato chlip into the test tubes, and I must Dry the potato chlip before weighting. 5- Prediction I predict that the lower the concentration of the sugar solution in the test tube the larger the mass of the potato will be. This is because the water molecules pass from a high concentration, i.e. In the water itself, to a low concentration, i.e. ...read more.

Conclusion

My method of carrying out the experiment was fairly accurate. I made sure to wash the test tube carefully for the two levels of concentration. The second experiment, I measured the same amount of solution in each time and stopped the stopwatch as soon as the time required to leave the test tube Is finished. I think that I should have used five different test tubes for the five different concentrations because this would be more accurate, fair as the test tubes will be dry. If I was to do the experiment again, I could improve the accuracy and reliability of the results by having a range of different concentrations. Also I could use the same amount of test tubes for the number of different concentrations I used. If I had more time, I could do additional experiments to investigate another factor such as the effects of varying concentration of a certain solt solution on the amount of osmotic activity between the solution and a potato chip of a given size. Improvements that could be made to this experiment: To repeat this experiment several times and record more averages in order to obtain a higher degree of accuracy. In my experiment, I believe this experiment was carried out to the best of my abilities, and is the optimum performance using all possible resources and time available. The results obtained, which seem reliable, supported my predictions. - 1 - 10 O.L. Biology 1/7 Coursework ...read more.

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