Wash that area with water and if you still have burns, blisters or rash than go hospital immediately. Fair testing: Before starting the experiments I will clean all the apparatus after each experiment, measure the oxygen from the meniscus point, I will cut each potato into exactly 1cm , for each experiment I will add 30ml of hydrogen peroxide solution and all the experiments will last 24 minutes so that I have done fair tests. Also I will be repeating the test 2/3 times to see if my results are correct. I will also keep the time and temperature same. I will also have to keep the volume of hydrogen peroxide same.

Diagram: Key factors The key factors that I will be varying are the surface area which will change the amount of oxygen produced as a result. The key factors that I will keep control of are the volume of the hydrogen peroxide solution, time and temperature. I will take about 5 or 6 readings/observations and repeat the experiment twice to get more reliable results. I have decided to draw graphs to observe a pattern/trend in my results. Results tables First set of results: Second set of results: Number of cubes Surface area (cm2) Oxygen produced (cm cubed) Time (minutes) 1 6

Conclusion: I have produced a graph to show the average results including a line of best fit. I found out that as the surface area of the cubes increases the amount of oxygen produced also increases. This conclusion matches up with my prediction.

Although the amount of oxygen produced decreased at 36 cm squared of surface area – I have explained why this occurrence has happened on my graph of averages. There has been some odd results on my first set of experiments where the amount of oxygen produced has decreased because I had to change the hydrogen peroxide and the next bottle I got was colder than the first one, so as I explained in the introduction that the temperature makes a difference to the amount of oxygen produce-‘In order for more collisions to take place the temperature must be increased meaning more heat energy needs to be given off.

Like I explained before more collisions will cause the rate of reaction to go faster. Again the more increase there is in collisions and the more temperature there is that will mean the volume of oxygen evolving will evolve faster but there will be no increase in the amount of oxygen evolving. ‘ On the second set of results it proves my prediction right because as the surface area increases the amount of oxygen produced also increases, and there have not been any odd results on the second set of results because I managed to use only one bottle of hydrogen peroxide through out the second experiment.

I had to warm up the bottle of hydrogen peroxide with my hands because to keep the temperature same which I have explained above and also to keep it a fair test. Evaluation: I am generally satisfied with my results as they prove right my prediction. The points on my graph are close to the line of best fit which shows that the results are reliable.

The procedure that I carried out was suitable for the experiment and it also shows by looking at my results that it was suitable. I must admit that my results are not 100 percent accurate because I did find it hard to cut the potatoes into exactly 1 cm cubed and also another thing is I found reading the amount of oxygen produced from the measuring cylinder from eye level quite difficult but I did get used to reading it as I did a lot of eye level reading.

To make the results more accurate and reliable could have been achieved by making a machine cut the potatoes exactly into 1cm cubes which can not be achieved by first time human cutters. Also the temperature was not kept constant because I was working with 30 or more students in the same room by which they all emit a little heat from their bodies which add together to give lots of heat in to the potatoes. So it would help if we worked in separate rooms to keep temperature constant.