I was investigating the effect that takes place when the amount of concentration of sugar is increased gradually by 10% each time. I used five different solutions as follows:
Distil H2O
10%
20%
30%
40%
I predict my results will prove that there is a connection and relation and my final graph will resemble this one:
I carried out this experiment five times using five differing solutions. I then calculated the average loss or gain in height of the potato chips using the five results from each solution.
Considerations
There were several other important factors I had consider in this experiment
They were;
-Temperature
-Water potential of potato initially
-Size of potato
-Mass
-Volume of solution potato chip is in
-Type of potato
-Surface area of potato chip
-Time left in solution
-Measuring device
If I was going to conduct a fair test, then I was going to control these other factors and that’s exactly what I did.
Doing the entire test at room temperature controlled the temperature.
To keep the water potential of the potato initially was kept by using the same type of potato, which has been treated in exactly he same way, e.g. cut without being washed.
The size of the potato is very important this is because it will have an effect on the mass and size of the potato whether it is an increase or decrease. I cut the potatoes to exactly the same size so this was a problem. The size was measured before and after the experiment to whether osmosis had taken place and to what extent.
The light intensity did not cause an inconvenience because all the experiments had been done in the same room.
The mass was a slight worry nut made sure or depended on the idea that if the sizes were equal so would the masses.
The volume of the solution that the potato chips were kept in had to be equal and fair. They had to be totally covered in the solution.
The instructions we were given were too fill the test tubes ¾ of the way up with solution keeping a consistent quantity.
The type of potato we were using had to be the same so I made sure that we used the same potato in order to certify that it was going to be a fair test.
The time left in the solution was approximately 30 minutes so I cleverly decided to measure the potato chips in the same order that they were originally placed.
The surface area of the potato chips, this must be the same because the amount of surface area exposed to the solution may affect the rate of osmosis. The thickness of the chip would already be the same so I just cut the length so that each chip was equal.
I had to use a ruler to measure the height after each chip was cut and tested. I made sure I used the same one every time and the same units on the basis of making sure my results would be accurate.
These preliminary results gave me an overall impression on the change in height loss when placed in varied concentrations of sugar solutions.
Final Results:
Planned method
I was supplied with all the necessary equipment needed to perform the experiment so all I had to do was arrange them and prepare everything else. The solutions had already been distilled so I didn’t have do that, but I had to cut 25 pieces of potato using a kitchen knife and ruler for accuracy and precision. I measured each potato chip making sure they were all the same height. I then poured the solutions into test tubes which I and placed on a rack. Whilst taking note of the time I placed the potato chips systematically in the test tubes and began the half an hour wait.I the measured and noted the height of the potatoes after half an hour and calculated th average loss to produce a more accurate results.
Obtaining Evidence
1. I took two average sized potatoes and checked they were both healthy and hard.
2. Using a standard kitchen knife I peeled the potato and cut out 25 equally sized potato chips on a white tile.
3. I had to be extremely careful whilst cutting the potato chips all to the same size as this could have affected my results.
4. Taking 3 test tube racks I placed all 25 test tubes and labeled each row of five with each differing solution which it would contain.
5. I carefully poured each solution into the correct test tubes and made sure I filled it up exactly ¾ of the way up.
6.I then re-measured each potato chip just to certify they were all equal.
7.I swiftly put each chip into the test tube and began the thirty minute count down.
8. Whilst I was waiting I prepared the area where the potato chips would measured.
9. After the thirty minutes were up I drained the potato chips and calculated the loss in height. I used a very systematic method to do this which was to measure them in the order they were originally placed in the test tubes.
10. I recorded all the results and calculated the average loss which gave me a very accurate result.
Evaluation
After the whole experiment i realised that what had seemed like a difficult task was in fact fairly simple. I think that all that was needed in this experiment was understanding and patience once you had these two things sorted then the rest was easy. I had to be extremely precise in all parts of the experiment because each one was as important as the next. Had there been any minor errors the consequences could have had a dramatic affect on my results.
Things like cutting the potato chips all to the same size and pouring exactly 3/4 worth of solution into a test tube were all important processes of the experiment so a lot of double checking was necessary. I had to at all times be aware of the restrictions which were present such as time, equipment and following careful instructions.
I do think the experiment was very successful as we obtained a large number of accurate results. I think hat it was a fair test, however if i were to repeat the experiment I would have measured the water instead of approximating. I could also have repeated the experiment so i had a set of preliminary and then final results which i could compare or merge. I could have possibly used cloned potatoes which were all the same or altered the shape i cut them for example into doughnuts because cells in the centre may have a different capacity of water, intake, distribution or different water potentials. To be even more definite i could have used a machine to cut them.
I am pleased with my results but there is definitely room for improvement. The thing i found most difficult was pouring the solutions into the test tube and making sure that they were all the same height. My overall evaluation of the experiment is that i think it will be very beneficial and good practice for future experiments. I did have a few anomalous results but the rest were all accurate.
