Apparatus:
Petrie dish, weighting scales, 5 test tubes, test tube rack, 5ml syringes, chopping board, scalpel, salt solution.
Method:
1) Cut the potato chip into roughly 5 equal pieces using the scalpel and the chopping board.
2) Weight each potato chip using the weighing scales and record the readings.
3) Get out 5 test tubes labelling them A – E, use the 5ml syringes to measure 5ml of water to put into each test tube.
4) Measure the correct amount of salt solution for each test tube using the 5ml syringes.
5) Place a sliced chip into each test tube for a set time of 2 minutes.
6) Check the temperature of the water at regular times, adding cold or warm water if needed.
7) Remove the chips from the test tubes after 2 minutes and weight each chip again.
8) Record the results for each potato chip.
9) Repeat the experiment 3 times.
10) Average the results.
Concentration range:
Results table:
Analysing:
I have used both a table and a graph to illustrate my results. The best graph to show my results for this experiment was a line graph. The line of best fit went through the recordings of solutions A, C and E, with B and D not far out. My results were quite reliable and I had no odd results. From looking at my graph and my results table I have found out that the potato chip decreased in weight in the solution with the most salt. We repeated the experiment 3 times to make sure our results were more reliable. In my hypothesis I predicted that the potato chip would decrease in weight in the high concentrated solution, I was correct. The water in the potato chip diffused through the potato chip into the high concentrated solution.
Evaluation:
My experiment was fair because I used the same apparatus and I only changed the concentration of the salt solution. However, the temperature may have affected the experiment. During the experiment the temperature of the water was changing, this became awkward. I tried to solve this problem by adding either warm or cold water to change its temperature but this also could affect the experiment because there will be more water in the test tube. Next time I could solve this problem by keeping the solution in one place and try to do the experiment all at once so it is more likely to stay the same temperature. To make my results even more reliable I could have compared my results with someone else’s. I could have done a second method involving length and size of the potato chip but I didn’t have time. That also can be something that I can do next time. There wasn’t any odd results, the ones that didn’t fit in the line of best fit weren’t far from it so that shows that my results are pretty reliable.
