Equipment -
- Knife
- Potato
- Tub
- Measuring cylinder
- Water
- Hydrogen Peroxide
- Test tube
- Bung
1. Collect one potato and cut it into two by one by one cm and only use fully exposed potato so no skin.
2. Then put 10 ml of H2 O2 into a test tube and put a bung over it use a bung with a connection with a rubber tube.
3. Then fill a tub with water but do not fill it up to the top but about three quarters of the way up
4. After this put a measuring cylinder that can hold at least 20 ml in the tub and fill it up facing downwards and read the mark the water is on and record
5. Then put the tube in the measuring cylinder with out taking the measuring cylinder out of the tub.
6. Then put the potato in the test tube put the bung on
7. Then shake the test tube and take down where the water has moved down and minus it form the start mark to get your result
8. Repeat all these steps again but use 15ml, 20ml, 25ml, 30ml of hydrogen peroxide.
Preliminary Results.
Graph-
Analysis- This graph and table of results clearly show that the higher amount of substrate used then the more oxygen is given off a 30ml produced optimum results so we are going to use that for our experiment.
Method-
1. Collect one potato and cut it into two by one by one cm and only use fully exposed potato so no skin.
2. Then put 30 ml of H2 O2 into a test tube and put a bung over it use a bung with a connection with a rubber tube.
3. Then fill a tub with water and make sure the water is 40 degrees to achieve optimum temperature to get this temperature use water bath water but do not fill it up to the top but about three quarters of the way up
4. After this put a measuring cylinder that can hold at least 50 ml in the tub and fill it up facing downwards and read the mark the water is on and record
5. Then put the tube in the measuring cylinder with out taking the measuring cylinder out of the tub.
6. Then put the potato pieces in the test tube put the bung on. 11. Then cut the potato that is 2 by one by one in four then half each piece. Then do steps 1-9
7. Then shake the test tube and take down where the water has moved down after 2 minutes and minus it form the start mark to get your result
8. Repeat all these steps again but use 15ml, 20ml, 25ml, 30ml of hydrogen peroxide.
9. Then repeat all of the above 2 more times and record.
10. Then cut the potato that is 2 by one by one in half. Then do steps 2-9
11. Then cut the potato that is 2 by one by one in four. Then do steps 2-9
12. Then cut the potato that is 2 by one by one in four then half each piece. Then do steps 2-9
13. Then cut the potato that is 2 by one by one in four then half each piece and half each piece again. Then do steps 2-9
14. Do step 13 but half each piece again.
Fair test -
To make sure that my experiment is fair I shall do the following things:
1. Heat the water to thee same temperature for each experiment
2. Make sure each potato is cut accurately
3. Make sure I put the same amount of H2O2 in each test tube
4. I will use the same potato for each experiment to make it a fair test.
Safe test -
To make sure that my experiment is safe I shall do the following things:
1. Be careful when using the knife.
2. Wear goggles to avoid H2O2 getting into the eye.
3. Wash my hands if any H2O2 gets any contact with the skin.
Results
Average results.
Average results graph.
Analysis-
Basically in my graph it clearly shows me that there is a strong positive correlation which is telling that my points are very close towards the line of best fit.
The patterns in my results are that they are all almost very close to the line of best fit showing that my results are accurate in some way.
These results explain that that the more catalyse surface area exposed then the more rate of reaction will occur because the more catalyse will be exposed therefore the more substrate can be formed into products and the more the enzyme can work, because it shows the higher the surface area the more oxygen produced. This directly corresponds with my prediction using scientific knowledge.
Evaluation-
The method I used was fairly safe and it was also accurate. This may have been because I had used good equipment and I heated the water to the right temperature just to get the right temperature for the experiment to work at its best.
The accuracy of my results was good because I did not see any clear indication of any anomalous using my tables but although this was the case when I plotted my results on a graph it shown there was one anomalous result it was the point where the potato was showing eight cm squared. This may have been because of these following points:
1. Because I may have cut the potato too much and there was pieces missing.
2. Because there was not enough hydrogen peroxide because I didn’t measure it well.
3. Because the temperature was not right so it would be not fair.
4. Or there was not a good part of the potato.
I think my method was a good one because I used safety and did a fair test to the best I could. To improve the reliability of the evidence I could have repeated the results again or to monitor the heat all the time and to take results every few seconds instead of every 2 minutes.
