• 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

    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 -

  2. Marked by a teacher

    Effect of nitrate concentration on the growth of Duckweeds

    5 star(s)

    proves that growth is favoured by nitrogen, as the duckweeds in 0% x 10-3 concentration of nitrates although had a higher water potential solution, did not have any nitrogen present so were not able to grow to their maximum. In 0.4% concentration, the presence of nitrates allowed the duckweeds to grow to their maximum.

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

    Additionally, the experiment was over very quickly and so timing at different intervals was very difficult as well as distinguishing the absence of the pink colour. To improve I thought it would be a good idea to use an indicator which was colourless in alkaline conditions and for example red

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

    During this trial we first started by putting in 20cm3 of milk with 20cm3 of bile salts and lipase. The reaction which resulted from putting them volumes was very fast so we decided to reduce the volume of the lipase and bile slats because my background informed me that when

  1. Investigate the effect of changing the sugar concentration on the rate of respiration of ...

    0ml sugar solution, 20ml water 0cm 0.01cm 0.1cm (10%) 5ml sugar solution, 15ml water 0.8cm 2.7cm 4.5cm (20%) 10ml sugar solution, 10ml water 1.2cm 3.5cm 5.9cm (40%) 20ml sugar solution, 0ml water 2.2cm 4.6cm 7.9cm To show my results graphically I have produced a sketched graph for my preliminary results: 8. 0% 0ml sugar solution in 20ml water 7.

  2. Investigation into the Effect on Pulse Rate & Breathing Rate During

    When Laurence and Saleh stopped exercising their heart adjusts. Parasympathetic nerves, primarily the vagus nerves slow down and steady the heart giving it more time to rest in noncrisis times. Both Saleh and Laurence's breathing rates were also recorded during the 2 minute period of exercise and 60 seconds of the resting period.

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

    I had to choose a sensible area to work in, with sensible measurements. From secondary opinions, it was suggested to use 15m by 15m. This was the right area to use within the two sites. I took out the measuring tape horizontally by 15m and brought it out by 15m vertically.

  2. Investigating the effects of Sodium Hydroxide concentration on Catalase

    Before I did my main experment I did a preliminaly test to found out the concentrations od sodium hydroxide will give me the best reslts, and how much of it to use, this is the same as the hydroxide peroxide thought I know I will use 10% volumn, so I

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