osmosis coursework

If the potato has got more sugar particles than the concentration then the potato will absorb the particles from the concentration this is because the quantity of the particles inside the potato is more than the concentration so it will pull the particles from the concentration to the potato. If the concentration got more particles than the potato then it will be the other way round.

Variables:

In this experiment

* We measured mass of each potato discs.

* We measure the time we left the potato in the concentration using a stop watch.

* We measured the thickness of the potato discs before putting it in the concentration.

* We measured the amount of different concentration.

* We measured the temperature of the room which was 20'C.

* At the end we measured the change in mass of the potato discs.

Apparatus that we used:

* Potato

* Petri dish

* Filter paper

* Different concentration

* Borer accurate scale

* Scalpel

* Measuring cylinder

* Vernal callipers

* Screw gauge micrometer

Method:

. First of all I drew the obtaining evidence table in my book.

2. Then I collected the equipments that we needed for this experiment.

3. Then I cut a tube of potato using a borer.

4. Then I cut 18 disc potatoes.

5. After that I took three discs of potatoes and measured the mass of each discs using an accurate scale.

6. Then I measured the thickness of each potato discs with screw gauge micrometer.

7. Then I measured 20 cm of concentration using a measuring cylinder then I poured it in to a Petri dish and start timing it.

8. I left the concentration for at least half hour.

9. After half hour I took the potato discs out of the Petri dish and put it on a filter paper by order.

0. I measured the mass of each potato discs and wrote it in my result table.

I did the same for the other 5 concentrations.

Obtaining Evidence

Concentration

Of

Sugar solution

Test

Initial potato

Mass

(G)

Final potato

Mass

(G)

Change

(%)

Difference

(%)

average

(%)

0.0

.25

.49

0.83.89

-16.11

47.45

2

.49

.42

04.92

-98.98

3

.28

.76

72.72

-27.28

0.10

.77

.28

38.28

38

20.66

2

.45

.51

96.02

-3.98

3

.50

.25

20.0

20

0.25

0.532

0.79

67.34

-32.66

26.7

2

0.645

0.592

08.95

8.95

3

0.494

0.803

61.51

-38.49

0.50

0.812

0.513

58.28

58.28

41.88

2

0.623

0.475

31.15

31.15

3

0.820

0.602

36.21

36.21

0.75

0.25

0.60

93.33

-6.67

2.38

2

0.82

0.67

22.38

22.38

3

0.68

0.74

91.89

-8.11

.0

0.93

0.50

86

86

45.69

2

0.55

0.49

.12

12.24

3

0.52

0.85

61.17

-38.83

Analysis:

In this investigation I found out that as the concentration of sugar is increased it will absorb the sugar particles in the potato and this will bring change in mass of the potato.

The results that I recorded during the experiment don't support my prediction maybe because we didn't do a fair test.

The shape of the graph that I end up with is completely different from what I predicted.

The percentage change suppose to go higher as the sugar concentration increase but in my graph I can see that from lower sugar concentration the % change decrease instead of increasing.

I predicted that as the amount of sugar particles in sugar concentration increases the mass of potato decreases and if there are more sugar particles in the potato than the concentration then the potato will increase its mass by absorbing the particles for the sugar concentration.

Conclusion:

In this investigation we as a group did our best to make it a fair test and get what we are aiming for.

My obtaining evidence doesn't support my prediction.

My result shows that at 0.10m the mass of the potato disc changed from 1.77g to 1.28g after leaving it in the concentration for 30 minutes. This means that the potato had less sugar particles than the concentration.

At 0.50mola the mass of the potato disc changed from 0.812 to 0.513 this means that as the concentration of sugar goes higher the potato will loose its particles and change its mass. At 1.0mola the mass of the potato changed from 0.930 to 0.500 this concentration brought a big change in the potato's mass because this concentration had lots of sugar particles init.

Evaluation:

In my opinion the experiment was easy to do but my obtaining evidence didn't support my prediction so this means that we didn't do a fair test even we repeated each concentration 3 times.

This maybe because the sizes of the potato discs were all different and maybe we didn't measured the mass accurately and brought an error in my calculation afterwards. And I think we used two different potatoes because we lost the potato and we needed 6 more potato discs so we use another potato.

The thing that I found hard was that we couldn't cut the potato discs in the same size and we wasted most of the potato trying to cut in the same size.

If I had to do this experiment again and to make it a fair test I would use a machine to cut the potato discs in the same size.

I would have same amount of sugar concentration in every test. And to also weight each potato discs on a digital and more accurate scale not to e.g. 0.00 but to 0.0000.

I have learnt a lot through out this investigation for example what osmosis where and how does it occur. And I used some of the apparatus that I didn't use before for example accurate scale, vernal callipers, screw gauge micrometer.

Hezbullah Skandari Page 1 of 6

Mr Jones

02/05/2007