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Testing the heart rate of Daphnia with concentrated caffeine

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Testing the heart rate of Daphnia's using different caffeine concentrations Hypothesis:- The Daphnia's heart rate will increase as caffeine concentration increases. Equipment:- Cavity Stick, Cotton Wool, Tally Counter, Microscope - Low power (x40) objectives, Stopwatch, Daphnia, Pipette, Beaker, 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? ...read more.


184 272 292 273 250 240 166 226 132 240 300 292 189 224 199 208 0.1 (Z) 116 194 174 222 238 226 295 256 221 300 320 300 0.2 (X) 271 182 170 246 220 260 246 196 218 300 0.3 (Y) 108 98 107 272 22 254 170 188 210 228 282 268 268 251 0.4 (V) 220 240 236 300 324 308 267 240 279 336 316 316 234 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. ...read more.


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. Biology 9th October 2007 1 ...read more.

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