A Biology 20 class wanted to investigate the endurance of fellow students related to the activity of muscle cells. A muscle is said to be fatigued when it is unable to maintain a certain level of performance. The students designed an experiment that used the number of repetitions of a muscle group to indicate the level of performance. Procedure: Each individual used the apparatus diagrammed above to perform three trials. First a 250 gram load was used, then 500 grams, and lastly a 1000 gram load was used. A 1 litre soft drink bottle was filled with the appropriate mass of water. (1 mL of water = 1 gram). The subject was instructed to raise and lower each mass rapidly -- about twice a second. The trial was considered finished if the subject could not raise the weight 3 cm or was unable to maintain a rate of 2 lifts per second. Between trials the subject had a 1 minute rest. During this time the arm of the subject could be massaged. I Questions: (a) What problem were the Biology 20 class investigating? (b) What was the manipulated variable in this investigation? (c) List at least two controlled variables you would have to consider in this experiment.
A Biology 20 class wanted to investigate the endurance of fellow students related to the activity of muscle cells. A muscle is said to be fatigued when it is unable to maintain a certain level of performance. The students designed an experiment that used the number of repetitions of a muscle group to indicate the level of performance.
Procedure: Each individual used the apparatus diagrammed above to perform three trials. First a 250 gram load was used, then 500 grams, and lastly a 1000 gram load was used. A 1 litre soft drink bottle was filled with the appropriate mass of water. (1 mL of water = 1 gram).
The subject was instructed to raise and lower each mass rapidly -- about twice a second. The trial was considered finished if the subject could not raise the weight 3 cm or was unable to maintain a rate of 2 lifts per second.
Between trials the subject had a 1 minute rest. During this time the arm of the subject could be massaged. I
Questions:
(a) What problem were the Biology 20 class investigating?
(b) What was the manipulated variable in this investigation?
(c) List at least two controlled variables you would have to consider in this experiment.
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