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Biology: Osmosis and Diffusion Lab using Potato Cores Class: 3B Mr. Boyer Name: Simon Han Abstract: In this experiment, we learnt about Osmosis and Diffusion through potato cores in different concentration of sucrose, (water, .2, .4, .6, .8, 1.0). We realized that the lower the concentration, the higher the potato cores weighed. However, our result was quite off for the potato cores in .8 sucrose concentrations. The graph should decrease, but our graph was decreasing and suddenly crosses the x-­‐axis then down again. Our graph had 3 x-­‐intercepts. The equation of our graph is y = -­‐46.56x + 34.76. Our x-­‐intercept of the best-­‐fit line is (1.34, 0). Although our graph and our results were off, it still partially backed up our hypothesis. Research Questions: How does Osmosis affect the weights of object in different concentrations? Introduction: All cells have membranes that are selectively permeable. In other words, they allow certain things in and certain substances are not allowed to enter the interior of the cell. The process by which water crosses membranes from regions of high water concentration to regions of low water concentration is called Osmosis. Osmosis is the process whereby water moves across a cell membrane by diffusion. Diffusion takes place when the molecules of a substance tend to move from areas of higher concentration to areas of lower concentration. Cells must tightly control the process of osmosis otherwise they will die. Plants with too little water will wilt. This happens when water moves out of the cells by osmosis. Without this water there is little pressure inside the cells and the plant can no longer support itself against the pull of gravity.

Hypothesis: The more hypertonic potato cores are to sucrose solution, the more weight potato cores gain. On the other hand, potato cores will decrease in weight when it is hypotonic to sucrose solution.

Variables:  Dependent: The final mass of the potato cores  Independent: Concentration of sucrose

 Controlled: Size of potato, time spent in solution, amount of solution Apparatus: • • • • • • • • • • Potato cores (4 per condition) Sucrose solutions (.2, .4, .6,