The Effect of Caffeine on Heart Rate
The aim of this experiment was to test the effect of caffeine on the
heart rate of a Daphinia (water fleas).
Hypothesis:
I prediction for this experiment is that an increase in caffeine on
Daphinia will increase the heart rate because caffeine is a stimulant
drug that increases the activity of the nervous system.
Equipment;
The equipment that I will use for this experiment is as follows:
* Culture of Daphnia
* Cavity slides and cover slips
* Dropping pipettes
* Distilled water
* Caffeine tablets
* Cotton wool
* Standard glassware (beakers, measuring cylinders)
* Stop watch
* Paper towels
* Light microscope
Method;
The procedure I will use is as follows:
* Place afew strand of cotton wool on a cavity slide to help
restrict movement of Daphnia. Transfer a water flea to the slide
using a large pipette. Remove the water surrounding it using
filter paper and add a few drops of distilled water. Use as much
water as possible to allow the water flea to maintain sufficient
supplies of oxygen. View the flea under a medium power and focus
on the heart which can be seen through its translucent body.
* Use a stop watch to record the number of heart beats in a minute.
Tap a pencil on a piece of paper for each beat and count all the
marks at the end of the minute. Record the results in an
appropriate table.
* Repeat the procedure using several different concentrations of
caffeine.
Results;
Concentration
Test 1
Test 2