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Testing the Effects of caffiene on Daphnia

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Introduction

Testing the Effects of Caffeine on Daphnia Hypothesis I believe that the pond water with caffeine will produce an increased heart rate compared to the normal pond water. Variables My dependent variable, which is what I will be measuring, will be the heart rate of one flea. My Independent variable will be the addition of caffeine to a sample of pond water. I will be using the water flea and also keeping constant the amount of water (approx). Planning Caffeine is used as a stimulant drug. This raises blood pressure by increasing the adrenaline in the body. It is also used as an insecticide by raising the heart rate so much that the insect suffers a heart attack. ...read more.

Middle

* Repeat at least three times to get a range of readings. * Then repeat this after adding a few drops of the caffeine water. * Average out the respective results to find an standard result. Whilst doing this experiment, you have to be very careful with the equipment. The microscope is expensive and may break quite easily as well as all other glassware. As these fleas are living creatures, there are some ethical matters attached to this experiment. Though we are bringing them out of their natural environment, we are using pond water, which is close to their natural habitat. In addition to this, these fleas are to be returned to their environment when the experiment is over. ...read more.

Conclusion

I am not sure if that is large or small for this type of experiment. This could be due to human error. The person counting could have missed a few beats or maybe even over compensated for a few beats. These can easily distort results and produce a wider spread of values than that which is acceptable. Other errors include the stopwatch being calibrated incorrectly but this would only produce systematic errors, which may not be too much of a problem unless a significant percentage of stop clocks were calibrated incorrectly. This could give some pairs a higher/lower value for the heart rate. (if +or- a second, could add a significant amount of extra/less heart beats in the time span) My average results for TEST A were slightly below the class average, whereas for TEST B, they were above. ...read more.

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