• Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month

Effect of caffiene on the heart rate of Daphia

Extracts from this document...

Introduction

´╗┐The effect of caffeine on the heart rate of Daphia. Hypothesis Caffeine mimics some of the effects of adrenaline and noradrenaline and increases the rate of concentration and relaxation of each heartbeat, so I believe the daphia?s heart rate will increase with the gradual increase in caffeine concentration. Therefore I predict a resultant positive correlation. Variables Independent variable is the heart rate of the daphia. This will be controlled by placing a daphia underneath a microscope and counting by the human eye, the number of times its heart beats. Dependant variable is the concentration of caffeine which is given to the daphia. This will be controlled through using the correct equipment e.g. volume beakers and pipettes etc. Controlled variable could be to choose daphia of the same age and size, as the heart rate will differ, for example in younger daphia their heart rate is faster as they are still developing or larger daphia as they have a bigger surface area to be covered so blood has to be pumped quicker. Uncontrollable variables(to an extent) will be the temperature of the daphia?s water as this can affect their heart rate also e.g. ...read more.

Middle

It is accepted that caffeine effects humans and daphnia in similar ways, they are still different organisms so will be effected in slightly different ways. Although the general effects- increasing and decreasing heart rate- should be the same, the amount of variation will almost certainly be different, because humans are much larger than daphnia, a much larger quantity of caffeine would be required to produce the same degree of change in the heart rate. To get results that are completely accurate for humans, a large scale medical study would have to be undertaken. When the daphnia is being observed under the microscope it is in close proximity to the lamp, which gives out heat, the little volume of water/concentrated caffeine concealing the daphnia, only requires a small amount of heat to raise the temperature. If the daphnia is under the microscope for just under five minutes, it?s likely to raise the temperature by several degrees, possibly increasing the daphnia?s heart rate. However this limitation can be counterbalanced as all daphia are under the same condition. Apparatus Daphia(water flees) A plastic transfer pipette A watch glass A dissecting microscope Beaker x2(one for used daphia, one for non-experimented daphia) ...read more.

Conclusion

Evaluation Although the hypothesis was proven to be correct, there were some anomalies found in the experiment (circled in the results table). These readings were much lower than the other repeats, this could be due to human error; misreading the heart beat due to the speed of contractions, or the size of the daphia; maybe the daphia used for that certain repeat could cope with the concentration of caffeine more effectively that the others for that certain concentration. Another explanation is that of the room temperature could have been at different temperatures at different times or at different areas in the room, for example near windows or radiators. This could have well affected the daphias heart rate. Equipment was also found to affect the results, to get a true reading of a daphias heart rate, more technical equipment was needed. It was literally impossible to get an accurate reading from the control group of daphia, never mind when the heart rates increased with caffeine. Equipment could be improved by using better microscope lenses and the use of a ?clicker? these pieces of apparatus would aid a better reading as I would of have a clear view of daphias heart rate to reading and a more sustainable way of counting heart contractions for the 20 second period. ...read more.

The above preview is unformatted text

This student written piece of work is one of many that can be found in our AS and A Level Energy, Respiration & the Environment section.

Found what you're looking for?

  • Start learning 29% faster today
  • 150,000+ documents available
  • Just £6.99 a month

Not the one? Search for your essay title...
  • Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month

See related essaysSee related essays

Related AS and A Level Energy, Respiration & the Environment essays

  1. Marked by a teacher

    Effect of nitrate concentration on the growth of Duckweeds

    5 star(s)

    unexpectedly small, such as 8 and 7 fronds, compared to 36 and 33fronds from the initial 8. So although there was the right increased amount of fronds in the concentration there was also a small amount of frond growth, which are anomalous results.

  2. Marked by a teacher

    Fighter Pilot A Statistical Analysis of Reaction time and its Correlation with Dominant ...

    5 star(s)

    reaction times between the dominant handed subjects and non-dominant handed subjects Alternative hypothesis; H1- Non-Dominant handed subjects will have a significantly higher reaction time than the dominant handed subjects Method Apparatus * A meter long ruler * Questionnaire - Appendix 1 * Record sheet - used to record results -

  1. the effect of bile concentration on the activity of the enzyme lipase during the ...

    During the test we found that the biggest pH drop in the smallest amount of time was seen when we carried the test out at 37oC which is the body temperature. Therefore we disregarded doing our actual method with the other two temperatures of 50oC and 30oC as 37 proved

  2. Investigate the effect of bile salt concentration on the digestion of milk by the ...

    By adding the buffer I am keeping the pH conditions the same, and therefore the enzymes' rate of reaction will only be affected by the variable I am changing and not other extraneous factors. The optimum pH of lipase is 8.0-9.0.

  1. The aim of this experiment is to research on the effect caffeine has on ...

    RISK ASSESSMENT, SAFETY PRECAUTIONS AND ETHICAL CONSIDERATIONS RISK SAFETY PRECAUTION Potential tripping Coats and bags tidied away before the practical starts and move carefully around the lab when handling heavy equipment (microscope).

  2. Weed study. Dandelions - descrption and characteristics. Investigation to dandelion distribution.

    So this was also reliable. > 40 Soil pots - These would be needed to place the soil samples. I would need 40 soil pots as I am implementing my investigation at two sites. I would take approximately a teaspoon amount of the soil, to test the pH level.

  1. Experiment. Hypotheses: The higher the concentration of caffeine the higher the heart rate of ...

    as possible, this can be done by using the same solvent (pond water) and using as much solution as possible to fill the cavity on the slide without a cover slip. Take care not to wet the objective lens this is an essential part of the experiment because if oxygen levels decrease the heart rate increase.

  2. How Caffiene Affects Heart Rate

    They have no bones in their body and have a shell around the body except for the head. They can reproduce rapidly & feed on algae and vegetation. Commonly known as the 'Water Flea'. Variables; The variables will be controlled so that the results concluded can remain fair and precise.

  • Over 160,000 pieces
    of student written work
  • Annotated by
    experienced teachers
  • Ideas and feedback to
    improve your own work