The temperature of each water bath does not have to be precise, just within the recommended range. Record the exact temperature as you collect your data.

LabBench Activity

Design of the Experiment II

It is possible to measure metabolic rate indirectly by measuring heart rate. In this activity, you will gauge the effect of temperature on metabolic rate by counting the heartbeats of Daphnia.

There are a number of possible procedures for "trapping" the Daphnia so that you can observe its heart under a dissecting microscope. Your instructor will show you the procedure to use.

Observe the Daphnia in a petri dish of water at three different temperatures. Select each magnifying glass to practice timing the Daphnia heart rate.