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How does caffeine affect heart rate?

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How does caffeine affect heart rate? Introduction This experiment is to investigate the affect of caffeine on the heart rate. Daphnia The Daphnia also sometimes called a water flea is a genus of Crustaceans that is found abundantly in small bodies of fresh water. Some of these are just large enough to be seen without a microscope in good light. Daphnia belongs to Kingdom Animalia, Phylum Arthropoda, Order Cladocera, Family Daphnidae, Genus Daphnia, and Species Daphnia pulex. It is usually found in fresh water, although there are some that live in salty water. It is an important link in the aquatic food chain. Daphnia has a small and semi-transparent body, which help one to study the effects of various drugs on the heart. It is a type of small crustacean and is generally 0.2 to 3.0 mm long. Apparatus We need * Culture of daphnia * Cavity slides * Standard glass ware (beaker) * Dropping pipettes * Filter paper * Cotton wool * Microscope Planning 1. In pairs, set microscope, stop clock, and the slide. ...read more.


Then we are made to exchange the slides. Random errors can occur by not following the standard procedure also carelessness can produce random errors as well. Implementing the plan 1. Set up microscope in pairs. 2. Set up the cavity slides 3. Take one slide and add 2-3 drops of ice water in it, this will later act as the heat sink. 4. Then place another on the top, facing the converging side up. 5. Using pipette, transfer a large daphnia from the pond water to the cavity slide. 6. Providing enough water will help to have sufficient amount of oxygen to the daphnia 7. Place few straits of cotton wool on the cavity slide to prevent the movement of the flea. 8. View the water flea under a low power compound microscope 9. Focus on its heart which can be seen through its translucent body 10. Use a stop watch to record the number of heart beats per minute 11. One person count beats while other tells time 12. Tap a pencil on a paper and count up the pencil marks at the end of the time period 13. ...read more.


124 122 138 147 150 136 Average 140 141 144 147 154 145 Caffeine 141 146 167 180 162 157 On daphnia 142 152 147 150 164 157 142 183 202 176 142 131 168 150 154 150 148 150 150 170 147 159 162 161 Average 142 155 172 146 162 160 Graph Validity /Reliability of the Results I think the results I got are reliable, because this activity is done 5 times by each student and there were 6 groups to do this so this is repeated 10 times and taken the average. In order to make the results valid I have controlled the variables that I think would have made an effect .the graph shows a trend that caffeine has an effect on heart rate. Summary It is clear from the results table and the graph that the heart rate of daphnia is high for those which was on caffeine. So I conclude that caffeine has a positive effect on heart rate .it can increase the heart rate. The results table shows that, as the time increases the heart rate also increases, this is because of the stress that it experiences. ...read more.

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