Osmosis Essay, Research Paper

Title: Osmosis in Potato Cells

I am traveling to look into: the diffusion of H2O by osmosis in works cells, when altering the concentrations of saccharose in H2O, and mensurating the alteration of mass of pieces of murphy left in the solution for 12 hours.

I predict that

I predict that the stronger the solution of sucrose the more mass the pieces of murphy will free. This is because the solution will be more concentrated than the solution in the murphy. So the H2O in the murphy will come out through the partly permeable membrane of the murphy cells into the more concentrated sucrose solution. This means that the mass of the murphy will diminish because the H2O from the solution will hold moved out of the murphy into the sucrose solution. When the concentration of the sucrose solution is weak ( weaker than the solution inside the murphy ) the murphy will derive mass. This is because the solution in the murphy is more concentrated than the sucrose solution. So the H2O in the sucrose solution will soak into the murphy by go throughing through the partly permeable membranes of the murphy cells because the murphy is more concentrated than the sucrose solution. This means that the murphy will derive mass because the murphy now has more H2O in it. This is all because in osmosis the partly permeable membrane in works cells will let the H2O in the lupus erythematosus concentrated side to ooze through to the more concentrated side.

Method

I started off my experiment by utilizing a knife and chopping board to cut up five little pieces of murphy 5cm, by 1cm, by 1cm. I weighed all the pieces of murphy before the experiment and made sure the pieces all weighed within 5 gms. I so put the pieces of murphy individually in petri-dishes. In the first petri-dish I used 20 milliliter of H2O, in the 2nd one I put 16ml of H2O and 4ml of saccharose. I so carried on altering the solution 4 milliliter at a clip. Here are the concentrations that I used:

Sum of saccharose ( milliliter ) Amount of H2O ( milliliter )

0 20

4 16

8 12

12 8

16 4

20 0

In each petri-dish I put 1 piece of murphy, which was labelled, weighed and the put palpebra on and so left for 12 hours. Then after 12 hours I weighed the murphy pieces doing certain there was no extra solution on them and repeated the experiment another 2 times. This allowed me to work out norms so that my consequences were really accurate.

Decision

My graph shows that the stronger the solution of sucrose the more mass the pieces of murphy lost. This is because the sucrose solution is more concentrated than the solution in the murphy. So the H2O in the murphy came out through the partly permeable membrane of the murphy cells into the more concentrated solution. This means that the mass of the murphy lessening because the

H2O from the solution moved out of the murphy into the sucrose solution. When the concentration of the sucrose solution was weak ( weaker than the solution inside the murphy ) the murphy gained mass. This was because the solution in the murphy was more concentrated than the sucrose solution. So the H2O in the sucrose solution will soak into the murphy by go throughing through the partly permeable membranes of the murphy cells because the murphy is more concentrated than the sucrose solution. This means that the murphy gained mass because the murphy now has more H2O in it. This was all because in osmosis the partly permeable membrane in works cells will let the H2O in the lupus erythematosus concentrated side to ooze through to the more concentrated side.

From my consequences I found that the mean solution of a murphy is 43 % saccharose, 57 % H2O. This means when the sucrose solution was 43 % saccharose there was no motion of H2O so at that place wasn T any mass alteration because the two concentrations were the same. My graph shows this rather clearly.

I besides have one or two anomalous consequences demoing on my graph. There are a few that are merely of the best-fit line, which is likely because the murphies were different so they have different concentrations or the sizes of the murphy pieces may be different. At the underside of my graph where the concentration is the strongest there is one consequence that doesn t suit the best-fit line at all good. This may be because the murphy can non shrivel up any more because all the H2O has already been taken out of it therefore no excess mass can be lost. This means that at the underside of the graph the best-fit line may get down to swerve off because the pieces of murphy can non free any more mass.

Evaluation

I am pleased with my consequences being accurate as they all shown the same thing ( that in osmosis a partly permeable membrane in a works cell will let H2O in a less concentrated solution to ooze through to the more concentrated solution ) . I found a few troubles that may hold varied my consequences a small. One trouble was cutting the pieces of murphy into the exact same sizes. This would do a difference because the surface country will be different so one piece of murphy may hold more or less sucrose solution exposed to its cells than other pieces. Besides some of the murphy pieces may hold had more solution covering them than others. So some murphy pieces may hold had more or less sucrose solution exposed to the murphy s cells than others. Twelve hours may non hold been long plenty for the murphy pieces to be in the solution. If I had done the experiment once more I would hold done some preliminary work to prove whether or non 12 hours is long adequate clip. One last thing is that different murphies have different concentrations so the consequences may change for different murphies. If I did the experiment once more I would hold a vaster scope of concentrations to give me a wider scope of consequences.