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What factors affect Osmosis in potato cells?

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Osmosis Experiment Aim: What factors affect Osmosis in Potato Cells? Introduction- What is Osmosis? Hypothesis Osmosis is the passage of water molecules from a weaker solution into a stronger solution, through a semi- permeable membrane. In this case, the tiny holes in the semi-permeable membrane of the potatoes will allow the water molecules to pass through in and out of the solution and the potato, depending on the concentration comparison of the two substances. When the water concentration is lower in the tissue, the water will enter inside the tissue of the potato, and the potato will gain weight. If there is very little difference in the two water concentrations, there shouldn�t be such a large in weight. If there is a higher concentration of water in the potato, the water will leave the potato. Plan There are several variables available for experimentation in this investigation including the molarity of the solution, the size of the chips and the time they are left in the solution. I will be varying the molarity of the sucrose and keeping size of the potatoes as similar as possible and the time they are left in the solution the same. In this experiment, I intend to investigate which factors affect osmosis in potato cells. Osmosis is when certain molecules are allowed on or out of cells and this is controlled by the semi-permeable cell membrane. ...read more.


have all been cut without being washed and peeled. I am also going to use the same balance to weigh my potato chips. This is because the measurements may slightly vary between scales. Safety I will be using a sharp knife and this is the only unsafe part of my apparatus; I will take care when handling and using it. Prediction For my main experiment, I predict that as the amount of H2O increases in the solution, the higher the mass, length and width of the potato. This is because water moves from a higher to lower water concentration across the semi-permeable membrane during osmosis; ie DILUTE STRONG (lots of H2O) (little H2O) As the amount of H2O lowers, the potato will gain less mass, or lose mass; get shorter and have a smaller diameter. As the amount gets higher, the potato will gain mass, length and have a larger diameter. I predict that if the potato cells are not fully turgid at the start of my experiment, they should absorb water through the osmosis process; causing an increase in weight, length and diameter. When the sugar solution is stronger than the cell sap of the potato cells, the chips should shed water through osmosis. The cells should lose their turgor; the potato will become lighter, shorter and less rigid. ...read more.


The range of concentrations was adequate but I could have created more concentrations if I repeated the experiment so that I would have more varied results. The cutting of the potatoes was the most difficult part of the experiment as although I was recording my results by length, width and diameter, it could have affected the surface area and so the overall rate of osmosis. If I were to repeat the experiment I could use a machine to cut the potato as it would ensure that all potatoes would be exactly the same weight and dimensions. I could have found a more accurate way to measure out the solutions and to determine the molar concentrations. I could have used a burette to ensure that I have an accurate amount of liquid in each test tube. I could also weigh each chip on a more accurate scale. I encountered one anomalous result; his may have been caused by human error. When I removed the chips from the test tubes and dried I may well have dried some potatoes more thoroughly than others and so some would have more excess water, which would add to the weight. If the experiment was repeated I could find another way to dry the potatoes that would ensure that all were dried in the same way for the same amount of time. Overall, I think that my experiment was successful and I was very pleased with the comparison of my results with my initial prediction. ...read more.

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