Equipment
6 beakers
Sugar Solution
Water
Labels
Potato (cut to the same size)
Knife
Ruler
Scales
Method (M=molar)
- Collect all your equipment sensibly
- Label all 6 beakers either 0m, 0.2m, 0.4m, 0.6m, 0.8m, 1m.
- Prepare and cut the potato into similar lengths, and masses. To end up with 18 bits of potato.
- Make sure you have weighed, and measured the length of each potato, and recorded these results.
- Put the 18 bits of potato to one side, as you will need these a little later on.
- Add the desired amount of sugar solution and water to the designated beakers.
- Pop 3 potato pieces in each beaker.
- Leave to one side for approximately a day or two to allow the osmosis to really start happening.
- After a day or two. Remove the potato from the beakers, repeat step 4.
- You are now ready to see if osmosis has noticeably taken place.
Fair Test
A fair test is where you keep everything the same except the one factor that you are changing. Carrying this out will make my results and conclusion more accurate.
To make my experiment a fair test I will make sure of a few things that the potato pieces weigh, and measure the length at the start of the experiment. Apart from that, I think most things I do will be carefully monitored. It is very important that I make sure I make this experiment a fair test, if it isn’t then the results I will achieve will be incorrect. To make sure this is a fair test I will take special care to make sure when I weigh all the potato; I weigh them all carefully and record the weighs correctly. I will also try to make sure the sugar concentrations are as accurate as possible, to prevent this experiment being unfair.
Results table.
Table to show average Lengths of potato.
Analysis
On the previous pages you can see the graphs I have drawn. The graphs show
* Average final length
* Original Mass
* % Average change in mass
From the graph, which represents Average final length I can see that the higher the sucrose concentration gets then the lower, the Average length seems to be. The graph has a positive correlation. There are a few results, which don’t follow the sequence of a downhill average, but even these aren’t anything for me to worry about as they do fit in with the results and experiment.
These graphs that I have drawn do seem to support my predication, in that I predicted the higher the concentration, then the smaller and lighter the potato cells will turn out to be. These graphs do reflect my prediction, as the results for 1M are a lot lighter and smaller than the potato cells which have been but in 0M.
When looking at the graph which shows the ‘Final mass length’ you can see there is an out of place result the third potato cell which was in the 0m sugar concentration has a final length which is way higher than the other two which were also in that same strength of sugar concentration. This could be because I have recorded the wrong length following the experiment, or a mistake that was made beforehand, when I first measured the potato cells.
That really is the only out of place result that I can see, which does not fit in with the general pattern of that graph.
Looking at my results table, there is no out of place results that I can see. They all seem to fit in with each other and all seem to reflect and support the predication I have made earlier on in the experiment.
The results along with graph show that the stronger the sugar concentration is, then the smaller and shorter in length the potatoes seem to be. I suppose this is because the water has a lower concentration than the potato does, so the water held in the potato which makes it heavy diffuses out of the potato, to the outer area.
This scientific reason would be supported by the fact that the shorter and lighter the potato measure at the end of the experiment, than the softer they seem to be, this is because of the reason I expressed above that the water has diffused out of the potato into the surrounding area.
Evaluation
The experiment I carried out, showed me that the concentrations of the sucrose solutions did affect the osmosis taking place, in the potato pieces. My results show me that:
Osmosis did actually take place in this experiment since the potato pieces changed in length size and mass. Pure water (with no sucrose solution added) proved to produce the greatest increase in length sizes.
So therefore I found out that the more concentrated the sugar solution becomes then the more decreased the overall increase in length turned out to be. All the results do confirm and support all my original predictions.
Looking back over my results table and the graphs I made after conducting the experiment and making these graphs, there are no abnormal results. There were one or two which were a little out of place, but I didn’t feel these were anything to mention and go into detail about as these were probably caused by the equipment I used as it more than likely wasn’t 100%.
If I carried out this experiment/coursework for a second time I would use more accurate equipment such as using more precise measuring equipment, as I feel this would probably improve my results a little bit. I believe I did carry out enough attempts for each Strength of sugar concentration as this gave me a variety of varied results, but I think I would benefit next time from doing more attempts for each one, to give me a wider range of results, and to see how the results continue to vary which would then allow me I feel to evaluate and analysis in a lot more depth.
I think the method I chose, and used to carry out my investigation was a good one. I don’t think I could have possibly done the investigation any other way to be honest, except from as I mentioned before to use more accurate equipment.
Further experiments that I could carry out, could be to try the same experiment on different cells, plants e.t.c just to see how the results vary from the ones I have received over the period of gathering the results and carrying out the investigation.
I believe I could have improved my experiment further, by using more accurate equipment. Carrying out more attempts per each sugar concentration, which would allow me to carry out a more in depth analysis, and I think would show up more abnormal results and results which don’t quite fit in with the other results I have gathered.
Conclusion
From this experiment I have found out that osmosis is present in potato cells, and I found out that the water has a higher concentration than the potato as the water molecules moved into the potato, and made them longer in length and heavier.
I conclude with, that the more concentrated a solution becomes then the smaller the cells will become as the water molecules move out into the surrounding area as it has a a lower concentration than the potato cells themselves.
By Lucy Nicholson