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This laboratory exercise is presented as an alternative to the traditional AP catalysis lab. The technique is easier for the students to use and yields better results. We have developed a technique at our school in which the students make a reaction chamber out of a dropper bottle.
Students dip dots of filter paper into the enzyme mixture (usually ground liver) and place them on the top side of a dropper bottle sitting on its side. Peroxide is added to the bottom side of dropper bottle and the whole apparatus is placed in a pan of water. Once the bottle is spun 180° the peroxide comes into contact with the liver-coated disks and start reacting. The bubbles generated are collected into the water-filled graduated cylinder and students measure volume of O2 generated by the volume of displaced water.
This system also allows for easy variations in the experiment. To use different percentages of catalase, we reduce the number of filter paper dots: 100%=4 dots; 75%=3 dots; 50%=2 dots; 25%=1 dot.
Please see accompanying photos & illustrations to help visualize this system.
For TEACHERS: How to make the reaction chamber?