Enzyme lab

For the experiment we were testing to see how much oxygen was created in a reaction of yeast and hydrogen peroxide. In order to test this we obtained a tub filled with water a graduated cylinder a ring stand, a rubber stopped a rubber tube and a glass cylinder and the yeast and hydrogen peroxide. We had to fill the tub with water about 3/4ths of the way full and then submerge the graduated cylinder in the water and leave it upside down. we then attached the graduated cylinder to the ring stand while leaving the opening in the water. Then we placed 10 mL of hydrogen peroxide in the glass cylinder. we attached the rubber tubing into the rubber stopper and had it ready to place back on the glass cylinder. we then added 1 mL of yeast and immediately placed the stopper on the cylinder. We had to quickly place the rubber tubing under water and inside the graduated cylinder. we kept track and at 30 second intervals we check the amount of air that had been created by the yeast and hydrogen peroxide reaction by counting the amount of bubbles and the how many mL the water had gone down in the graduated cylinder. we continued to check for 5 minutes. we then repeated this experiment using 1o mL of hydrogen peroxide and .75 mL of yeast.

I was expecting for there to be less air produced in the experiment where there was only .75 mL of water. However, we saw the opposite effect. though the results may show this (see attachment) I believe there may have been some human error. I think that there was air already trapped inside the rubber tubing and it was released into the graduated cylinder. Meaning that there was a significant amount of air that had been measured that was not created by the hydrogen peroxide/yeast reaction.

*Note- I had issues uploading the data table so it will be in an e-mail