This investigation starts with a guided procedure where students gather data on the heart rate of daphnia when the organism is exposed to 1% ethanol. Daphnia are tiny crustaceans that are visible with the naked eye, through a microscope or stereoscope and will be needed to see their heart rate. Daphnia are very interesting to observe because they are transparent, with the organs easily visible.
Part 2 of the investigation asks students to design and conduct an experiment that will test another variable, such as glucose or temperature. Part 2 is inquiry based (open-ended) and requires students to gather data, formulate conclusions and turn in a short lab report.