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

Does Caffeine affect heart rate?

Extracts from this document...


Does Caffeine affect heart rate? Aim: To investigate the effect of caffeine on the heart rate of Daphnia Introduction: I will be measuring the heart rate of a Daphnia once I have exposed it to different concentrations of caffeine to see if caffeine affects heart rate. I have done a preliminary experiment so that I know which concentrations to use, how long to measure the Daphnia's heart rate for and so that I have practised counting the Daphnia's heart beat. This means that I will harm the Daphnia the smallest amount possible, will know how long the experiment will take me and will be fully prepared. My hypothesis is: when the concentration of caffeine increases, the heart rate of the Daphnia will also increase. I think this because caffeine is a stimulant of the central nervous system, cardiac muscle, and respiratory system. This means that it increases your body actions, such as heart rate, blood pressure and metabolism. I believe that it will have the same effect on Daphnia so that their heart rate increases as the concentraion of caffeine increases. Variables: My independent variable is the concentration of caffeine, whilst my dependent variable is the heart rate of the Daphnia. ...read more.


This means my partner will make up each solution and give them to me in a random order so that I do not know which solution is which concentration. Therefore I will not be thinking that the heart rate should be higher or lower than the solution before, so will not sub-consciously change the rate at which I am counting. Apparatus: ?2 cavity slides-To put the Daphnia on so they are in a smaller space so that it is easier for me to measure their heart rate. ?2 Daphnia-To measure the effect of caffeine on. ?2 measuring cylinders-To accurately measure out the solutions. ?10 beakers-To mix the solutions together in to create the right concentration. ?0.5% Caffeine solution-To put the Daphnia in. ?Distilled water-To change the concentration of the caffeine. ?10 Pipettes-To transfer the solutions from the beakers to the cavity slides. ?Microscope-To magnify the Daphnia so that I can see its heart and will be able to count the number of times it beats. ?Heat Sink-To place over the lamp below the microscope to stop convection occurring. ?Stopwatch-To measure the amount of time I count the heart rate of the Daphnia. ...read more.


Likewise Daphnia number two had a mean heart rate of 240 beats per minute in Distilled water, and a mean heart rate of 754 beats per minute in 0.5% Caffeine. I have no anomalies from either set of results. My graph shows me that the two sets of results are very similar and follow exactly the same pattern. My results back up my hypothesis that when the concentration of caffeine increases, the heart rate of the Daphnia also increases. Evaluation: My results are accurate and reliable because my results are very close together. In order to improve my results I would take five readings for each concentration rather than three and I would also test five Daphnia rather than two. This way I would get a wider range of readings and they would be even more accurate than they already are. If I was do the experiment again then I would count the Daphnia's heart beats for 15 seconds rather than 10 seconds, because then I would only have to multiply the result by four so I think the results would be slightly more accurate. Apart from this I think the procedure I used worked very well. ...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 Exchange, Transport & Reproduction 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 Exchange, Transport & Reproduction essays

  1. Marked by a teacher

    Human Reproductive System

    4 star(s)

    If the egg does not become fertilised within 24 to 36 hours after ovulation, it will deteriorate and be removed by the body's immune system, like any other dead cell in the body. Fertilisation and implantation Fertilisation involves the fusion of sperm and ovum or oocyte to form a zygote, a fertilised egg.

  2. Marked by a teacher

    The effect of caffeine on heart rate

    3 star(s)

    Other glassware should be handled with extra care. Low Crowded environment- clutter and unnecessary fragments Make sure table and work space is clear. Working in groups of 2 or 3 is recommended. Roles should be allocated to each experimenter. Objects that are not in use should be put away.

  1. Marked by a teacher

    Daphnia experiment - Does caffeine affect heart rate?

    3 star(s)

    In humans, caffeine acts as a stimulant drug, causing increased amounts of stimulatory neurotransmitters to be released. At high levels of consumption caffeine has been linked to restlessness, insomnia and anxiety, causing raised stress and blood pressure. This can lead to heart and circulation problems.

  2. Marked by a teacher

    Daphnia experiment - Does caffeine affect heart rate?

    3 star(s)

    4. Use a tiny piece of cotton wool; put it onto the curve of the cavity slide, this will prevent the daphnia from moving, making it easier to count the heartbeats. 5. Using a pipette, transfer a daphnia into the 0ml caffeine solution. 6. Leave them to accumulate for 2 minutes.

  1. Peer reviewed

    Effect of Caffeine on the Heart Rate of Daphnia

    3 star(s)

    However, the protective effect was found only in participants who were not severely hypertensive (i.e. patients that are not suffering from a very high blood pressure). Furthermore, no significant protective effect was found in participants aged less than 65 years or in cerebrovascular disease mortality for those aged equal or more than 65 years.

  2. Effect of Caffeine on the Heart Rate of Daphnia

    Tea is another common source of caffeine. Although tea contains more caffeine than coffee, a typical serving contains much less, as tea is normally brewed much weaker. Caffeine can be absorbed rapidly into the bloodstream from the gastro-intestinal tract. It reaches maximum concentration within an hour.

  1. The Endocrine System

    The body requires volumes of glucose in order to create ATP. The amount of ATP demanded will fluctuate, and therefore the body regulates the availability of glucose to maximise its energy making potential. Two hormones are responsible for controlling the concentration of glucose in the blood.

  2. Blood System Assignemnt

    The capillaries create a large surface area of blood exposed to the cells of the tissue so there is less distance for the food and oxygen to travel into the cells and for CO2 to travels from the cells in to the blood.

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