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We will be investigating osmosis and its effect on potato chips.

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Introduction

Mahmoodul Shah 28/12/2002 Biology Coursework: Osmosis Introduction We will be investigating osmosis and its effect on potato chips. Osmosis is the movement of water molecules across a partially permeable membrane from a region of high water concentration to a region of low water concentration. Planning In this investigation I will be investigating the effect of osmosis on a set size of potato chip in different molar solutions of sucrose solutions. During the investigation I will have to conduct objectives carefully considering I will be cutting potatoes and working with test tubes. However if an unfortunate incident does occur then I should inform the teacher straight away to avoid any danger of happening such as somebody cutting themselves. During the experiment I need the equipment listed below: * 25 cm3 measuring cylinder * Knife * 2 tiles * Test tubes * Solution of 1m sugar * Distilled water * Pipette * Ruler * Electronic scale accurate to a hundredth of a gram For accurate results I need to make the investigation as fair as possible. During the investigation I will be making many measurements and to obtain accurate results I will need make the investigation as fair as possible I will need to measure precisely to obtain accurate results and most likely to leave it to a set measurement such as that "All potato chips need to measure 10cm" to reduce time. Also during the investigation I will need to measure the weight and that will be done through the electronic scale mentioned above. ...read more.

Middle

Osmosis takes place between the cytoplasm and the solution outside the cell. The changes happening inside the cell due to osmosis bring about visible changes in the plant. However when the plant cell is placed in less concentrated solution water passes through the cellulose cell wall and the cytoplasm and eventually into the vacuole leading to the cell becoming turgid. This happens when water flows through the cell wall and into the vacuole. The pressure of the water in the vacuole increases and the water presses the cytoplasm against the cell wall. When the cell contains as much water as it can the cell is fully turgid. However when plant cells are put in higher concentrated solution water passes out of the vacuole, out of the cytoplasm and into the surrounding solution. The pressure of the vacuole on the cytoplasm decreases and the cytoplasm pulls away from the cell wall. The cell becomes limp something like a balloon and the cell is called plasmolysed or flaccid. Obtaining To start this experiment we needed the necessary equipment. The equipment consisted of a 25 cm3 measuring cylinder, a knife to cut the potato chips, two tiles, and 6 boiling test tubes in a test tube rack, a solution of 1 molar sucrose (sugar) solution, distilled water, a pipette, and then the potato chips. My partner and I wanted to see two sets of results i.e. a duplicate. This would lead to more precise results and because we were doing duplicates we needed a further 6 boiling tubes. ...read more.

Conclusion

My results were good because they did show the general pattern on what I had predicted. However there were a few odd results. If we look at graph 2 we see in two places where the change in weight does not fit the general line. This is at 0.15 molar sucrose solution and at 0.35 molar sucrose solution. We can see at 0.15 molar sucrose solution that the change in weight has increased and the line which should go directly down has gone up a little. This is the same case at 0.35 molar sucrose solution. There could be reasons why this happened. One of the reasons could be that while cutting the potato excess skin of I could have cut a bit of the potato of. This would have effected the surface area and the overall osmosis effect upon the potato chip. Another reason could be that when drying the potato chip before it was put into a solution I could have dried one potato chip than the other and recorded the results. This meant that the amount of water in each potato chip would have differed from one another, and the overall osmosis upon the chip would be different. This could be the reason why I got the odd result. This reason could count for when taking out the chip from a solution. I could have taken a chip(s) out of a solution and dried one chip more than another. This meant that the weight would have been altered and the odd results occurred. However I think the experiment was successful because if I compare it to my initial prediction it is very good and the graphs show the general line of what should have happened. ...read more.

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