Investigate the effect of enzyme and substrate concentration on the initial rates of reaction

Potatoes contain the enzyme catalase which breaks down hydrogen peroxide cork bore and cut up the potato into evenly sliced disks into 5,10,15,20 and 25 disks sets hydrogen peroxide in conical flask with gas syringe add each number of potato disks to the hydrogen peroxide and measure the volume of oxygen produced every 10 seconds for 1 minute repeat this 3 times for each set of disks to get mean no disks present as control