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Osmosis. To investigate which sucrose concentration is the same as the concentration of cell sap inside the potato by narrowing down the primarily larger ranged concentrations of the cell sap

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Introduction

Science Coursework: Osmosis Aim: To investigate which sucrose concentration is the same as the concentration of cell sap inside the potato by narrowing down the primarily larger ranged concentrations of the cell sap. We will do this testing an extensive variety of sucrose concentrations to discover the concentration that gives the smallest mass change in the potato. Intro: Osmosis is the diffusion of a liquid, although it is often assumed to be water; it can be any liquid solvent through a selectively permeable membrane from a region of low solvent potential to a region of high solvent potential. The selectively permeable membrane must be permeable to the solvent, but not to the solute, resulting in a pressure gradient across the membrane. See below: The image is showing us that because there is a lot more water in the cell to the left and very little in the cell to the right, the water is travelling from the region of higher water concentration i.e. the cell to the left to the region of lower water concentration i.e. the cell to the right. As we can see in the image (right), only the water molecules are actually moving. http://www.himalayancrystalsalt.com Turgor pressure is the positive internal pressure in a cell resulting from osmotic pressure i.e. the cells expanding and be in danger of bursting, water pushing outwards from inside the cell because they contain too much water in a certain amount of space divided by a selectively permeable membrane. ...read more.

Middle

with exactly the same equipment. Equipment: * Five different concentrations of Sucrose solution: 12%, 14%, 16%, 18% and 20%. * 2-3 Potatoes * 6 Boiling Tubes * 1 Boiling Tube rack * 1 Measuring Cylinder * 1 Graduated Pipette * Top Pan Balance measuring to 2dp * 1 Size 6 Cork Borer * Ceramic Cutting Tile * Small Cutting Knife (scalpel) Safety: Scalpel: Be careful not to whirl around the scalpel as it could cause serious damage to yourself or people around you. Boiling Tubes: Again be careful not to swing around boiling tubes as you could drop and break them creating serious hazard. Also hold boiling tubes firmly because if your grip is weak, the boiling tube can again fall out of your hand and break. Cutting tile: Do not throw these around as their edges are quite sharp and can cause serious harm to the people around you. Method: 1. Cut six equally sized potato chips using the same cork borer. 2. Measure the mass of each potato chip using a top pan balance to two decimal places. 3. Measure and pour 25cm3 of sucrose solution into 6 boiling tubes. The five boiling tubes will contain these six concentrations of sucrose solutions: 12, 14, 16, 18 and 20 %. Sucrose Concentration (%) Starting Mass of Potato Chip (g) Average Final Mass of Potato Chip (g) Average Change in Mass of Potato Chip (g) ...read more.

Conclusion

Lastly we have repeated this experiment three times to increase reliability. Repetition of the experiment helped us make the results more reliable because if there were any anomalous results we would be able to spot them easily by looking at the three sets of results and noting down the major differences. Preliminary Work Preliminary Equipment: Five different concentrations of Sucrose solution: 10, 20, 30, 40 and 50%. * 2-3 Potatoes * 6 Boiling Tubes * 1 Boiling Tube rack * 1 Measuring cylinder * Top Pan Balance measuring to 2dp * 1 Size 6 Cork Borer * Ceramic Cutting Tile * Small Cutting Knife (scalpel) Preliminary Method: 1. Cut six equally sized potato chips using the same cork borer. 2. Measure the mass of each potato chip using a top pan balance to two decimal places. 3. Measure and pour 25cm3 of sucrose solution into 6 boiling tubes. The six boiling tubes will contain these six concentrations of sucrose solutions: 0% i.e. pure/distilled water, 10, 20, 30, 40, 50%. Preliminary Results: We discovered the following results after conducting this experiment. Sucrose Concentration (%) Starting Mass of potato chip (g) Final Mass of potato chip (g) Change in mass (g) Increase or decrease in mass 0 1.00 1.43 0.43 Increase (+) 10 1.00 1.23 0.23 Increase (+) 20 1.00 0.82 -0.18 Decrease (-) 30 1.00 0.71 -0.29 Decrease (-) 40 1.00 0.60 - 0.40 Decrease (-) 50 1.00 0.44 -0.56 Decrease (-) ?? ?? ?? ?? John Smith Yr.11/Sc1 Page 1 of 9 Miss Pittaway ...read more.

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