Osmosis Experiment.

Apparatus

Cork Borer

Potato

Sugar solutions (0.00M, 0.15M, 0.30M, 0.45M, 0.60M, 0.75M)

Distilled water

Tweezers

Scales

2 Petri dishes

Marker pen

Knife

Cling film

Measuring cylinder

Fair test: To make this experiment a fair test I will need to make the potato disks the same size to make the experiment identical I will also need to put the same amount of solution in each Petri dish, Also use the same size Petri dish. I will also need the same number of potato in each dish. I will also remove remove any skin on the potato.

What I did: First I got out my apparatus, next I bored my potato and made all the cylinders the same length and chopped the potato into equal sized pieces and then I weighed them and recorded it and then put the potato slices labelled in the Petra dishes and used the sugar concentrations and added to the appropriate dish. Then I covered the dishes in cling film and left it for 24 hrs. Next I took the cling film off took the potato out of the Petra dishes and weighed them again and recorded it. Then I cleared the equipment away. I covered the petri disks with cling film to stop oxygen and bacteria contaminating the experiment

Results

Results before added sugar solution

Sugar Solutions(M)

Mass at the start (g)

Mass at the start (g)

0.00

0.15

0.30

0.45

0.60

0.75

2.35

2.05

2.27

2.08

2.26

2.21

0.96

.65

2.12

.90

2.00

2.20

Results after sugar solutions

Sugar Solutions (M)

Mass at the end (g)

Mass at the end (g)

0.00

0.15

0.30

0.45

0.60

0.75

2.86

2.65

2.63

2.20

.91

.61

2.36

.93

2.69

2.05

.81

.68

I decided to make my results more accurate, I would work out the ratio by dividing the mass at the start by mass at the end

Results Sugar solution (M)

Ratio 1

Ratio 2

0.00

0.15

0.30

0.45

0.60

0.75

0.82

0.77

0.80

0.95

.18

.37

0.90

0.85

0.83

0.93

.10

.31

I then worked out the mean of my results by adding column 1 to column 2 and dividing by 2

Results

Mean ratio

0.00

0.15

0.30

0.45

0.60

0.75

.27

.19

.21

.41

.73

2.02

I used the mean ratio to draw the graph

Conclusion

The Results show some Patten. For example the 0.00 is a lower concentration than the 0.75 results, which is higher. So that 0.00 0.15 and 0.30 results gained weight and 0.45 0.60 and 0.75 lose weight so somewhere between 0.30 and 0.45 there will be a balance.

My graph shows a more or less straight line so my prediction is correct. I used my graph to work out the concentration of the cell, which will be when the ratio is 1.

Evaluation

Some of my results don't suite my graph or my pattern 0.60 and 0.15 these mite be because of the potato being a slightly different size, this is probably due to human error in future experiments I mite use a template or a shape cutter to get it more accurate. Also filling the Petra dishes full of solutions when filling them there could have been to much or too little solution but into the Petra dish this could also have been because of human error. Also when covering the dishes overnight with cling film some of the cling film may not of covered some of the Petra dishes.

In future experiment I will make sure I can get my results more accurate and also I could try other experiments in other fruits or vegetable to find out if they have close results