This experiment is to find out how different temperatures affect the rate at how an enzymes activity differs , using catalase and hydrogen peroxide.

Time

I believe this because at 0 the measuring cylinder will have no oxygen and as the catalyses (celery) is added to the hydrogen peroxide the catalyses will act faster and so more oxygen is produced, but as the hydrogen peroxide runs out (gets broken up) the oxygen being produced will reduce and eventually stop.  

For this experiment I will need:

Heat proof mat

Bunsen burner

Tripod

Gauze

Ice

Glass beaker

Thermometer

2 boiling tubes

Syringe (5ml)

Delivery tube

50ml measuring cylinder

20ml measuring cylinder

Margarine/sweet tub

Stop clock

Hydrogen peroxide

Liquidised celery

Water

1. first I set up the equipment up (as shown in the diagram)
   
2. I put the water in the beaker with the ice and 2 boiling tubes 1 with the hydrogen peroxide and 1 with the celery.  
   
3. Then I took the temperature until it reached 10°C I then put the hydrogen peroxide into the boiling tube with the celery and put the delivery tube on the boiling tube and then measured the amount of oxygen every 30 seconds.  
   
4. We did this with 20°C, 30°C, 40°C, 50°C and 60°C. using the ice and the boiling water to produce the temperature

I did a trail experiment before I did my real experiment.  I did this because than I would know what to do when it come to doing the experiment for real, as it is important to do this experiment in one lesson as the hydrogen peroxide can change after a period of time the aspects that can affect the hydrogen peroxide are:

Ultra violet light

Temperature

I used for my trial experiment:        5ml of celery

                                                30ml of hydrogen peroxide

                                                50ml measuring cylinder

I have changed my experiment

I will now use:   2ml of celery

                                                20ml of hydrogen peroxide

                                            20ml measuring cylinder

I have changed these because the celery and the hydrogen peroxide were both to much and the reaction bubbled over the boiling tube.  I have changed the measuring cylinder because I do not need a 50ml one and a 20ml is a lot more accurate.

I will also use these temperatures:            20°C

                                                        30°C

                                                        40°C

                                                        50°C

I have chosen these temperatures because there is a wide range of them and also I believe they will make a good graph and we will be able to see were the enzymes stop and start to work.                                          

I am going to make this experiment a fair test by making sure I use the same equipment, the same measurements and make sure I can get the same temperature.  Things I cannot control are the temperatures going up or down as the experiment is happening and if the hydrogen peroxide changes between experiments. There also maybe more cells in different parts of the celery and I could use different amounts during different experiments.        

I believe my experiment was a success because I predicted accurately and I believe I did the experiment to the best of my ability.  But next time if I was to do the experiment again I would use different equipment:

I could improve my experiment by using more accurate equipment

This equipment could be:

                                The measuring cylinders

                                The stop watch

                                The test tubes

I could use instead of the measuring cylinder a gas syringe this is a syringe that moves up as more gas is produced this could be more accurate to read and measure the gas. This also stops any of the gas leaking out as I am putting the stopper in the test tube to collect the gas as the Hydrogen peroxide is being put in. there is also another way of adding the catalyses to the Hydrogen peroxide as shown in the diagram below, you put the Hydrogen peroxide in one side on the other side of the partition than the catalyses this way the reaction doesn’t start till the stopper is on and the cylinder is tipped so the Hydrogen peroxide and the catalyses react.

 Also I could use a computer to produce the measuring of the gas as computers are more accurate and can count the gas at the millisecond it hits the time, instead of some one using human eye as this is not accurate.   Also I could change what I measure, I could measure instead of the gas produced I could measure the weight of the experiment and take times to see the difference in weight.    

If I was to do this experiment again would also use the equipment changes listed below and I would make sure all the Hydrogen peroxide I use each time I do the experiment are the same by testing them for there Ph.  I would do more experiment with a wider range of temperatures so that my experiment would have more accurate average results. This would also make my graph show more anonymous results.