Osmosis lab of potato in three types of waterDocument Transcript
Osmosis Lab Investigation1. General Purpose: The general purpose of this lab is to investigate the effect that a solution has on a livingcell. As solutions can be classiﬁed as a hypertonic or a hypotonic solution, the results would varyon whether which solution is used. The results of this investigation will be quantiﬁable and will bemeasured by their weights.2. Question: What effect does distilled water, glucose and saline have on potatoes if they are immersedin the solutions for a period of time?3. Hypothesis: From general knowledge, I predict that the glucose solution will have the greatest effect ona piece of potato because it’s concentration is the highest, thus through the process of osmosis,the potato will lost most of it’s water and will shrivel. Because this solution has the highestconcentration, water will need to be transferred across the selectively permeable membrane inorder to establish a concentration equilibrium.4. Variables:Independent: The type of solution usedDependent: The mass of the potato piece after it has been put in the solutionsControlled Variables: Size of potato used, Location, The time that each potato piece is in thesolution5. Materials:• 9 slices of potatoes• Knife and a cutting board• Cylinder slice cutter• 9 test tubes• Test tube rack• Distilled water• 15 % saline solution• 15 % glucose solution• Electronic balance• Masking tape• Tweezer6. Procedure:1. Wash the potato in order to remove all dirt and residue2. Using the cylinder potato cutter, cut out about 4 to 5 pieces out3. Using a knife, cut the cylinders of potato horizontally by 2 cm each4. Measure their weight on an electronic balance5. Label all the test tubes according to their solution with masking tape6. Record their weight on the test tubes7. Place each piece of potato in their own individual test tubes
8. Fill each test tube with their assigned solution until the whole piece of potato is submerged9. Leave all the test tubes in a test tube rack and place them in a shaded place10. Come check on the experiment later in 3 days11. Record their ﬁnal weight7. Data Table and Analysis: Type of Weight before Weight after placed Average Average Percentag solution placed in solution in solution (grams) weight weight e of (grams) before after change (grams) (grams) (%) Glucose 3.02 3.12 3.22 2.74 2.78 2.85 3.12 2.79 10.57 Saline 3.29 3.08 3.20 3.01 2.74 2.90 3.19 2.88 9.72 Distilled 3.18 3.01 3.32 N/A N/A N/A 3.17 N/A N/A Water8. Graph: Percentage)of)change)in)mass)a;er) the)process)of)osmosis) 12" Percentage)of)Change)(%)) 10" 8" 6" 4" Percentage"of"Change"(%)" 2" 0" Glucose" Saline" Dis4lled" Water" Type)of)Solu7on)9. Conclusion: During this investigation, the results were very clear however, one type of solution madethe outcome very difficult to determine. By the time we came back to check on our experiment, allof the potato pieces in the distilled water solution was completely dispersed. The material wasunfeasible and was not able to measured its weight. This was a major setback for ourinvestigation, nevertheless the other results came out just ﬁne. To conclude, I accept myhypothesis as it states that the glucose solution will have the most effect on the potatoes, whichcame out true. The percentage of change was the greatest compared to the others. Unfortunately,we did not have the data for the distilled water solution, which made the results of this experimentquite unclear. However, with the data we have, I can determine that the glucose solution made thehighest percentage of change. One source of error was also the temperature of the room which wecould not control. The temperature of the room might have affected the rate of which osmosisoccurred. I were to perform this experiment again, I would have used a bigger piece of potatosince it would have displayed a much clear change in mass. The smaller piece was ineffective as itwas completely disseminated by the time we checked on them again.