It catalyzes the conversion of hydrogen peroxide into hydrogen gas and oxygen gas. Mrs. Bastone's class used the Vernier Oxygen probes and the Labquest2 tablets to gather their data. They had some trouble getting meaningful results. Not all of the groups were able to calibrate their probes. Apparently the electrodes that sense the presence of oxygen have a limited life and eventually are not sensitive enough to pick up the voltage changes caused by the presence of oxygen on their surfaces.
Ms. Davies' class used the Vernier Gas Pressure probes in place of the Oxygen probes and all of her groups got better results when measuring the pressure within their reaction vessels as the oxygen gas built up over time. Mrs. Bastone plans to repeat the experiment with the Gas Pressure probes after the Spring Recess.
In both classes the students altered an established protocol to examine different factors that might affect the amount of gas produced overtime. Some of the independent (manipulated) variables used by the students in their experiments were: temperature (room temp, above room temp, below room temp), pH (acidic, neutral, basic environments) and catalase sources (beef liver, calf's liver, chicken liver, apples, strawberries and potatoes).
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| The weighing dishes in front of the boiling water bath contain a strawberry in one and pieces of potato in the other. This lab group was comparing the gas production from these two sources of catalase. The student also appears to be preparing a test tube of enzyme source to be boiled to see the effect of high temperatures on enzyme activity. |
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| One can clearly see the the bubbling gas produced when macerated beef liver is added to the hydrogen peroxide in the reaction vessel. In the lower right hand corner of this picture you can see a printout from one of this group's previous runs. |
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