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The aim for this Biology coursework is to investigate hoe the concentration of sodium chloride will affect the mass of potato chips that will be the same length and have same width

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Introduction

Biology Coursework: To investigate the factors which affect osmosis (Planning) The aim for this Biology coursework is to investigate hoe the concentration of sodium chloride will affect the mass of potato chips that will be the same length and have same width. The time factor for the chips will be the same to make it a fair test. The main variables throughout the investigation will be the mass, the length and the concentration in which the chips are kept in. Scientific knowledge of osmosis Osmosis is the movement of water particles across a semi permeable membrane, from a dilute solution to a more concentrated solution, until equilibrium is established, i.e. the same number of water particles on either side of the membrane. As the potato cell contains a more dilute solution. Water will pass into the solution to try and balance both things out. If the salt solution inside the vacuoles of the potato cell is less dilute than the solution in which it is planted in, water will enter the cell vacuoles in which the chips will gain mass and length. How ever, as the osmotic pressure builds up inside the vacuoles less water molecules will pass into it. Again when the osmotic pressure inside the vacuoles is the same as the water pressure outside there will be the same number of water molecules entering and leaving the cell. In this case equilibrium is relived. When placed in the solution water will pass out of the cell as the more concentrated solution is outside the cell. ...read more.

Middle

. * 15ml * 1.5m (the morality I want) to get 22 ml of salt solution. Now that I know how much salt solution to put in I need to put in water to makes sure that there is exactly 30 ml of solution in each beaker. * Then after 24 hours I will take them out, rinse them on filter paper and reweigh them. * I will repeat this experiment using different solutions and concentrations Safety To make sure that the experiment is safe I need to make sure that I am wearing goggles throughout the investigation. Furthermore, I will not be leaving any equipment on the table alone as anything could happen. If left on the table without supervision, there could be a spill or even shattering which could lead to one of my friends being injured. I will be not throwing any thing around and just make sure am careful not to spill any solution or water on the floor. Preliminary experiment results I have done a preliminary experiment to make sure if what I was doing was correct and any improvements that I could have make for my real experiment. These are the findings of my experiment. I did this experiment in two different solutions, one on 2 m solution and one in 1m solution. Concentration 1st mass 2nd mass Change 2m 3.32g 2.67g 0.65g 1m 2.34 I didn't get to record this experiment because I forgot to record the weight of the chip after the experiment. ...read more.

Conclusion

When the measurements got a bit tricky, that is to say we had to measure out 1.5ml, we used a smaller cylinder, ones were it goes only up to five centimetres of volume. There were some problems that encountered me when measuring accurately mainly due to the confusion between certain apparatus and their properties, however, these problems were overcome instantly once realized. The pattern I expected, was that as the molality increased than the mass loss will also increase, I saw that this pattern was followed by the experiment, because as we measured the different chips in different solution, after the experiment, the chips in the more concentrated solution lost quiet a lot of weight, whereas the chips in the lower concentration gained weight. I have shown this in my graphs and my results tables. I think that my results are reliable because the points on the graph is a straight line so my results must be accurate. If I done this experiment again I would improve it by making sure that the potato chips are the same length. Another way in which I could improve is that I need to be quicker in measuring and placing the chips into the solution, I say this because, the chips I put in first have had a longer time to go through the process of osmosis, and the chips I weigh after the first ones have an unfair advantage as, as they have had longer time for osmosis. So I need more than one person measuring and placing the chips in the solution, so we don't tamper with the results. ...read more.

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