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My main aim in this experiment is to find out if osmosis occurs in a potato, and how it affects the potato in different molar solutions of sucrose and water.

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PASSIVE PROCESSES Aim My main aim in this experiment is to find out if osmosis occurs in a potato, and how it affect the potato in different molar solutions of sucrose and water. Planning Before actually planning the experiment, I will do some research to find out about osmosis, and matters related to it, so that I can make predictions. And figure out a way to make this investigation fair and safe. Planning ahead would help me find out how to do what, when, which should lead me to good results at the end of the experiment. Osmosis The movement of water molecules across a partially permeable membrane from a region of high water concentration to a region of low water concentration. In a higher concentration of water there is a lower solute being called a weak or dilute solution and a low concentration of water is a higher solute being called a strong or concentrated. In a semi permeable membrane water divides to two solutions from high to low until both are equal. This water will move across the semi permeable into cells where there is lower water concentration by osmosis, this makes cells swell (turgid). Hypothesis Osmosis is the passage of water molecules from a weaker solution into a stronger solution, through a partially permeable membrane. In this case, the tiny holes in the 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 gradient of the two substances. ...read more.


If the volume of one solution in a test tube is higher or lower than another, will affect the pattern of results later on. We will also make sure that the potato is fully covered by the 6 different kinds of solutions. This is because, is the potato isn�t covered up by the solutions, the effect of osmosis might not occur to the fullest. Small things such as a dirty test tube, and a slightly cracked measuring cylinder could still affect the results, and therefore we will take these into account as well. Variables The several different factors that affect the rate of osmosis: Potato tissue: The number of cells that make up the tissue also help in the taking in or out of the water from or to the semi-permeable membrane increasing or decreasing the process. Potato mass: The more the weight of the potato the more likely for the tissue to have more cells passively working on the process. Water volume: The more or less water means a dilute or concentrated solution which increases or decreases the diffusion of water. Sucrose solution : The molarity of sucrose in the solution means the solution is either high or low water concentrated so controlling the amount of water diffising in or out of the cell. * These are classified under three types of variables. Fixed variables : these are factors I will keep the same in the experiment for a fair test: a) Length of potato b) ...read more.


Percentage (%) 0.0 1 5.87 5.89 0.02 0.41 2 5.81 5.84 0.03 0.62 3 5.85 5.88 0.03 0.62 Average A 5.84 5.87 0.03 0.55 0.2 1 5.85 5.85 0.00 0.00 2 5.83 5.83 0.00 0.00 3 5.84 5.84 0.00 0.00 Average A 5.84 5.84 0.00 0.00 0.4 1 5.87 5.69 -0.18 -3.70 2 5.66 5.51 -0.15 -3.22 3 5.74 5.62 -0.12 -2.53 Average A 5.76 5.61 -0.15 -3.15 0.6 1 5.87 5.63 -0.24 -4.93 2 5.86 5.57 -0.29 -5.97 3 5.88 5.55 -0.33 -6.76 Average A 5.87 5.58 -0.29 -5.89 0.8 1 5.81 5.49 -0.32 -6.65 2 5.62 5.22 -0.40 -8.66 3 5.86 5.53 -0.33 -6.79 Average A 5.76 5.41 -0.35 -7.35 Analysis of table The table above shows that the more sucroce in the solution the less the weight of potato after bieng put in the solution. As osmosis Is diffusion of water from a high to a low concentrated region the concentrated solution will have a low water concentration so water will diffuse into it making the potato swell but the dilute solution will be high in water concentration so water will diffuse from the potato to the solution making the potato shrink. From the table we obtained decreases or increases in percentage and the potatos that had decreased or increased were classified under the three variation contents in solutions which are: * Hypotonic: The solution with the lower concentration of solutes e.g 0.0M * Hypertonic: The solution with the higher concentration of solutes e.g 0.4M, 0.6M, 0.8M * Isotonic: The solutions being compared have equal concentration of solutes e.g 0.2M From the variation contents in solutions the cells changed and I classified the changes under the three types of plant cells: ...read more.

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