Water.
Controlled:- Timing/Exposure to caffeine,
Variables Timing of Daphnia under the microscope,
Timing of Measurement.
Repetition:- Each test uses a different Daphnia, a minimum of 5 tests must be done for each caffeine concentration.
How Are:- Range of Caffeine Concentration,
Independent Caffeine Tablets,
Variables Equipment to measure volume of water,
Changed?
Safety Issues:- Careful when transporting:
- Daphnia,
- Slides,
- Microscopes.
Ethnical Issues:- Keep Daphnia in the Caffeine as long as instructed, and then transfer Daphnia back into recovery (water).
Analysis:- In this experiment using the Daphnia, with the results given we found that there was no correlation between the Daphnia’s heart rate and caffeine concentration.
Evaluation:- In this experiment the reliability of the results were very poor because of the variation of results. There were multiple reasons for errors in our results, for example there was the possibility of counting errors because of hand-eye co-ordination, and there was also a possibility of temperature changes. When transferring the Daphnia from the caffeine to the slide that the temperature was affected ultimately changing the Daphnia’s temperature and therefore altering the heart rate.
Our results could have also been affected by the fact that different Daphnia were used for each of the tests, this was because we had to ensure no harm came to the Daphnia during our experiment.
One random error was the counting problem; this is because the counting was very inaccurate due to the equipment we used. We also had systematic errors, for example we had to use different Daphnia for each test therefore altering our results. We had to use multiple Daphnia’s to ensure the Daphnia were not harmed in the tests.