Research question: how is the different temperature effect (10, 20, 30, 40 and 50) rate of reaction in enzyme catalase?

Aim: The aim of this investigation is trying to find how the temperatures affect the rate of reaction. What is the optimum temperature for enzyme catalase?
Equipment use:
Procedure:
* Filled water bath with water at 20 degrees * Filled the measure cylinder with water, and upside down put the cylinder into the water bath. (make sure there is no gas in the cylinder) * Measure 20ml hydrogen peroxide and pour into flask * Using delivery tube to connect the measure cylinder and flask. One end put in measure cylinder and the other end put on top of the flask through a rubber stopper. * Double check everything is prepared nicely * Put 5g of mash potato into the flask and cover with the rubber stopper. At same time start stop watch * Look the measure cylinder, when there is no water in the measure cylinder, stop timing and record it. * Same procedure for other temperature * Repeat every temperature 5 times
Variables:
Independent variable: different temperatures – 10, 20, 30, 40 and 50 degrees Dependent variable: rate of reaction Control variable: * Concentration of the hydrogen peroxide (ml): in this investigation, hydrogen peroxide is a substrate. If the concentration of substrate is increase, the substrate molecules will increase as well. Hence, this probably increase the time of substrate collide with enzyme, thus, the rate of reaction is going to change. To control this variable I will use measure cylinder to measure 20ml of hydrogen peroxide into the flask, and look the level at right position – not look too high or too low, your eyes should be a straight line to it. * Amount of mash potato (g): we use mash potato as the enzyme catalase. More mash potato is likely to have more enzymes, if the amount of the mash potato is not controlled, there