Investigate the Osmosis in Potato Rods in Various Concentrations of Salt Solutions

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Investigate the Osmosis in Potato Rods in Various Concentrations of Salt Solutions

Introduction:

Osmosis is the movement of water molecules across a partially permeable membrane from a region of high water potential to a region of low water potential. It can be affected by several different variables including concentration of salt solutions. When a plant cell is put in pure water it will become turgid and it will not burst due to the presence of a cell wall and a large permanent vacuole and when it is put in a concentrated solution it will be plasmolysed, on the other hand when an animal cell is put in pure water it will burst due to the absence of the cell wall which is only present in the plant cell and if is plant cell is put in a concentrated solution it will shrink. What is the water potential?

The water potential of a solution is a measure of whether it is likely to lose or gain water molecules from another solution. A dilute solution, with its high concentration of water molecules is said to have a higher water potential than a concentrated solution, because water will flow from the dilute solution to the concentrated solution
(from a high water potential to a low water potential).:

Pure water has the highest water potential because water molecules will flow from it to any other aqueous concentrated solution even if this solution is a highly dilute solution.

Variables that affect the osmosis process in the potato rods:

Ø Independent variables: The Difference in concentration of salt solutions: This will affect the osmosis in the plant cell as I will prepare five different concentrations of the salt solutions and they are: 0.0, 0.3, 0.5, 0.7, 1.0and this is how they are prepared:

- For preparing the concentration of 0.0 I used pure water.

- For preparing the concentration of 0.3: I measured 3 cm3 of the salt solution by using the syringe and poured it into the test tube that is labeled 0.3, then I measured 7 cm3 of water and poured it into the same test tube.

- For preparing the concentration of 0.5: I measured 5 cm3 of the salt solution and poured it into the test tube that is labeled 0.5, then I measured 5 cm3 of water and poured it into the same test tube.

- For preparing the concentration of 0.7: I measured 7 cm3 of the salt solution and poured it into the test tube that is labeled 0.7, then I measured 3 cm3 of water and...

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... points on the graphs were plotted as accurately as possible practically.

All my results supported my prediction I made and helped me to make a strong trend in the graph.

Although, I might have got few anomalous results but that is to be expected, I may be have measured any substance which I am using wrong or not accurately. I repeated the experiment two times to get the accurate average results and to ensure that I had not made any mistakes and so as not to have any anomalous results in my experiment and there wouldn't be any chance for error to occurs.

My results seem reliable as I am basing my results' reliability on a hypothesis and my own prediction. I repeated the same experiments using different concentration of the salt solution or change the temperature so as to help the rate of osmosis in the potato rod.

Also for more accurate results, I could extend my coursework by testing the same brand of potatoes using different substances. By this
I mean using a different thing instead of salt, i.e. sugar or maybe any fruit juice. Then I could find out whether osmosis occurs differently with different things diluted in the water. I could even use different vegetables and fruits.

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