Both ethanol and caffeine are present in many consumable goods such as beers and coffee (Lab Notebook). Both drugs are known for causing physiological differences in organisms. It is important to be aware of the potential ramifications these substances since they are so widely used and ingested.
In humans, heart rates were increased slightly with the additional of ethanol (Abdel-Rahman 1987). In rats, heart rates were both increased and decreased with the addition of ethanol depending on the level of stress the rats were in (Arciero 1998). In humans, caffeine did not affect heart rates (Sparrow 1987). Different ages of humans had heart rates that were not affected by caffeine (Umemura 2006).
The purpose of this experiment was to test if the quantity of ethanol and caffeine increases or decreases the heart rates in Daphnia magna. We predicted that the heart rates of the Daphnia would rise when exposed to ethanol, yet would remain the same when exposed to caffeine. We also hypothesized that the higher the concentration of the drug in the solution, the more effect the drug would have on the organism.

Methods
We conducted the experiment on Daphnia …show more content…
1% concentration solutions had a significant difference according to the p-value (Table 1). The 0.5% concentration solutions and the control solution did not have a significant difference (Table 1). The more concentrated the caffeine and ethanol solutions were, the more the heart rates decreased (Table 1). Comparatively, the heart rates of the Daphnia were lowered by ethanol solutions more than they were by the control (spring water) and caffeine solutions when accounting for concentration differences (Table 1). This can be seen by the larger percent effects of ethanol when compared to the percent effects of the control and caffeine counterparts (Table 1). T-tests determined the differences in heart rates are significant (Figure