Apparatus:
- Ruler (15cm)
- Scalpel
- Small cutting board
- Core borer
- Sugar solution (0%, 5%, 10%, 15%, 20%, and 25%)
-
Measuring cylinder (100cm3 )
- Boiling tubes
- Test tube rack
- Potato
- Stop clock
Diagram:
Method:
six potatoes were cut into 20mm cylindrical pieces using a core borer and checked with a ruler to ensure all six pieces were the same length to ensure a fair test as we are looking for a change in weight. The pieces were then weighed and the results were presented in a table. After this each cylindrical piece was put into a different strength solution (there were six strengths ranging equally from 0% to 25%). They were left here for a recorded amount of time, as each potato must only be in the solutions for 30 minutes. They were then reweighed and this second set of results was shown in the table of results. This method was repeated three times for accurate and precise results. All three times the experiment took place in a laboratory and was a safe experiment as no dangerous chemicals were used.
The below are the table of results for all three experiments conducted:
Table of results for experiment 1:
Table of results for experiment 2:
Table of results for experiment 3:
Recording the results of the weight after each experiment was very easy. There was little hassle involved. Therefore producing an accurately detailed result table. Table of results to show the average amount of weight gained/lost over all three experiments:
To find the average the following formula was used:
(Change 1 + change 2 + change 3) : 3 = Average
Analysis:
From these experiments, the table of results and line graph helped me to find that my predictions were correct. In lower concentrations of sucrose, Osmosis takes place and the potato chips become turgid. In higher concentrations of sucrose, Osmosis takes place but the potato chips become pliable. As the concentration in the solution became more intense, the potato lost weight. For instance, the average difference in weight for 0.00% sugar solution was 0.17 grams, while for 25% the average difference was –0.34. This happened because there was a high concentration of water, in the 0.00%. Outside of the potato is a high concentration of water, while inside the potato is a low concentration of water, but a high concentration of sugar. So, by way of osmosis, the water from outside moved into the potato which made the size increase resulting in heavier potato pieces. The same works for a high sugar concentration outside, the potato will release some of its water ensuing it losing weight. So the higher the sugar solution, the more weight will be lost this was what had been predicted, and through having sufficient background knowledge an accurate hypothesis could be accomplished.
It was noticed that the second and third experiments both had exactly the same weights before osmosis took place; this meant that the second weights were also the same and proved that the experiment-taking place both times was accurate and was made sure to be a fair test. However some of the gaps compared to the first test were quite big, for example in the 10.00% solution the first change gained 0.03grams but in the second and third experiments it decreased by 0.04 grams this is quite a considerable loss considering the second and third results were identical. Possible explanations for this could be that the sugar solution was measured wrongly or there was an error in recording the results. Alternatively, it may have been left in the solution slightly longer than planned therefore giving them maximum exposure to greater osmosis.
Evaluation:
In conclusion, to all the information found in this investigation it was felt that the experiments were a success. A reasonably informative graph could be produced from the results, the experiment was repeated enough times for an adequate analysis to be made. However if the experiment was to be repeated again it would be sensible to leave the potatoes in their solution for a longer amount of time as to give the experiment ample time for osmosis to occur and therefore much more defined results. Another thing that could have made the results more precise would have been a measuring scale that went up to three or more decimal places as to ensure perfect results. Overall, the results were adequate, the aim was realized, the prediction was correct and it was a fair test; therefore producing a successful investigation of finding the effect of sugar concentration on osmosis in potato chips.
By charley lennard
