Osmosis Experiment

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Topic: Osmosis
Materials: Potato cylinders, 20 percent sodium chloride solution, three test-tubes, test-tube rack, scalpel blade, Gel ink pen, syringe-10cm^3, Plastic ruler with mm, tile, forceps filter paper, Masking tape. Method: 1) Three test-tubes, A, B and C were labeled and initials of experimenters were applied with the date: January 29, 2013. 2) A syringe was used to put 10cm^3 of water in tube A and 5cm^3 in tube B along with 5cm^ 20 percent sodium chloride solution and 10cm^3 20 percent sodium chloride solution in tube C. 3) Three cylinders of potato were removed from a petri-dish and placed on the tile provided. One end of each was cut to a 90 degree angle, then cut all to the same length of 30mm 4) One potato cylinder was put in each test-tube and was covered with 3m masking tape provided, then the exact time was labeled: 11:39 a.m. 5) Potato Tissue was left for approximately 21 hours and removed from the test-tube afterwards. 6) The contents of each test-tube were poured into a petri-dish and the cylinder removed and blotted with filter paper, throwing the liquid away from the petri-dish after each cylinder was removed. 7) The length and texture of each potato cylinder was recorded in a table. Discussion:In the experiment, I believe the phenomenon to take place is osmosis. Osmosis is the movement/diffusion of water molecules through a selectively permeable membrane from an area of high concentration of water molecules (high water potential) to an area of a low concentration of water molecules (low water potential). From previous knowledge I know when a plant cell is put into a solution with the same concentration as the cell contents, this is referred to as isotonic, some water molecules move in and out. Due to no concentration gradient, no net flow. When a plant cell is placed in less concentrated solution than the contents of the cell it’s referred to as hypotonic, some water molecules move out of the cell but more move into the cell. The cell...
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