Independent: Caffeine conc.
Dependent: Daphnia heart rate
Control: Temperature Vol. solution Daphnia stress Daphnia size Acclimatisation time Daphnia species
Method: Remove Daphnia & place in cavity slide w/ distilled water Leave 5 mins acclimatise, then observe, count heart beat under microscope for 30s x 2 calculate beats/min. Repeats w/ 2 Daphnias Repeat again with diff. conc. caffeine solution. 5 diff conc. = 3 repeats in each conc.
Outcome: Caffeine conc. increased, heart rate increased.
Evaluation Notes: Ensure Daphnia same size If left too long under micropscope, temp increased (due to lamp) = increase heart rate Count heart beat inaccurate High conc. may kill Daphnia Ensure enough data collected