Aim: Prove that an administration of caffeine on Daphnia has a close-to-immediate positive
effect on the heart rate of Daphnia, this is due to the fact that caffeine is a stimulant which
affects heart rate due to the release of hormones. The objective of this investigation is to
investigate the effect of caffeine on Daphnia.
Hypothesis:
If the concentration of caffeine is increased, then the heart rate of Daphnia would then
increase. Caffeine is a stimulant so Daphnia's heart rate would increase when exposed to
the caffeine solution.
Variables:
Independent:
● Caffeine concentration (M)
Dependent:
● Heart rate of Daphnia
Control:
● Volume of solution - the same number of drops should be used each time.
● Size of daphnia - the size of the daphnia should be around the same size for repeats.
● Acclimatise time - Daphnia should be left in a caffeinated solution for the same
amount of time to acclimatise.
Risk assessment
Hazard Risk Safety precautions to take In emergency Risk
level
Biohazard Contamination Disposable Latex gloves must be Lab technician must be Low
worn throughout the duration of notified.
practical - hands should be
washed with soap after handling
daphnia.
Broken glass Injury from Caution should be taken when Glass shouldn't be Low
sharp object handling glassware, it should be removed from wound,
kept away from the edge of the medical assistance must
worktop. be sought
Chemicals - Flammable, Eye protection must be worn Lab technicians must be Medium
Ethanol irritant to skin throughout the practical, room notified, necessary action
and eyes must be well ventilated and should be taken.