Part of The Student Room Group

  • 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...

Introduction

Does Caffeine affect heart rate? Hypothesis I think caffeine will increase the heart rate of the Daphnia. I think this because caffeine is a stimulant that causes more stimulatory neurotransmitters to be released than normal, and so will increase the rate at which the heart muscles works/beats. Apparatus * Culture of Daphnia * Cavity Slides - to place flea on to view under a microscope * Dropping pipettes - to pick up fleas as they are too small to handle * Distilled Water - to act as a control * Ice Water - to cool the Daphnia so the light used when using the microscope does not heat it causing the heart rate to increase causing a systematic error * Caffeine Tablets - crushed and used as the independent variable * Stopclock - to time the length of time (1 minute) the experiment lasts for * Paper Towels - to blot the pond water away off the cavity slide * Microscope - to view the Daphnia to allow a measurement of the heart rate to be taken * Light - used with the microscope to allow the Daphnia to be seen Method 1. Using a dropping pipette drop a Daphnia and some distilled water onto a cavity slide 2. ...read more.

Middle

Variables The dependant variable in my experiment is the heart rate of the daphnia. The independent variable is the concentration of caffeine in the solution I gave them. There are other variables I can control such as the temperature (replacing the ice water before each experiment and turning the light off when not using the microscope) and if the Daphnia is pregnant or not (as this may increase the caffeine intake of the flea). The size of the Daphnia is uncontrollable if I repeat using a different flea therefore I will avoid this, as well as this reason using a different flea may mean a faster or slower intake rate. Reliability To ensure my results are reliable I will repeat them and exclude any anomalies therefore I will not use a method that cannot be repeated and I have chosen equipment that I am familiar with using to increase precision (My familiarity with how the equipment works will reduce errors). Also I will repeat my experiment until I have concordant results. Errors To prevent any systematic errors I will prepare and apply the solutions but then ask a friend to count the heart beats without telling them which solution is on the daphnia. By doing a blind test like this it prevents personal bias. I will also make sure that the microscope's lenses are correctly in place before starting. ...read more.

Conclusion

Without using very sophisticated computer-linked equipment I do not know how else we would measure the dependant variable. And so using the apparatus available to us in school it would be the best way of measuring the heart rate of the Daphnia. Conclusion I cannot draw very valid conclusions about my results when there are errors with my method and I have anomalous results, but based on experiments 4-6 and my graph I can recognise a trend that did support my hypothesis. It shows that as the number of caffeine tablets in the solution increased so did the heart rate of the Daphnia: the results for experiment 4 for example are a positive example that supports my hypothesis; the value for my control was 198bpm, and Caffeine 3 was 320bpm; with all other values lying between these numbers. This happened because the amount of caffeine was increased and so the heart rate increased. This is because in humans caffeine is a stimulant drug. It increases the amount of stimulatory neurotransmitters that are released. Neurotransmitters are chemicals that are released by the brain which allow an impulse from one neurone to pass to another neurone. The increased amount would mean that impulses travel from each neurone at an increased rate meaning that muscles are stimulated to work at a quicker pace therefore the heart rate increases. ...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

or


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

    Consequently the information that is presented on this website must be reliable and accurate since the university must check the information it publishes on its website to make sure its accurate. * http://en.wikipedia.org/wiki/Enzyme - Used for background information on enzymes.

  2. Affect of caffeine on heart rate of Daphnia

    ethanol, on the heart rate. Equipment: o Culture of daphnia o Cavity slides o Dropping pipettes o Distilled water o Caffeine tablets o Cotton wool o Beakers o Measuring cylinders o Stop clock o Filter paper o Microscope The method- The variables involved in this experiment are- The concentration of caffeine= independent variable.

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

    either bind to the active site and therefore it cannot be turned into its product. The enzyme is denatured, often permanently. This causes a drop in the rate of reaction. The results of my experiment were very interesting and significant.

  2. In this experiment I aim to find out if caffeine has an effect on ...

    to light, they are also exposed to heat in which they aren't used to. Ethical Issues It should be understood that any experiment involving living organism always rises up bioethical issues. While performing experiment involving living organism can bring greater advances in science, it should not be forgotten that the

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

    A few strands of cotton wool are placed around the Daphnia to ensure it is held in place and doesn't move while it's been observed under the microscope. An extra drop or two of water is added to prevent the Daphnia from dying as the cotton wool tends to absorb pond water.

  2. Free essay

    Does Caffeine Affect Heart Rate?

    This may occur every 3 days. A female may have as many as 25 broods in its lifetime, but the average is about 6. We chose the Daphnia because its heart is visible, on the back of its head, so we will be able to time the heart rate and compare it to a human's.

  1. Does caffeine affect heart rate

    Daphnia are small crustaceans. Daphnia are one of a number of small aquatic crustaceans commonly called water fleas because of their saltatory swimming style. They live in a variety of aquatic environments, ranging from acidic swamps to freshwater lakes, ponds, streams and rivers.

  2. How does caffeine affect the heart rate of Daphnia?

    Place the slide onto the stage of a light microscope and focus it on the beating heart of the Daphnia. 4. Count the number of heartbeats in 20 seconds and multiply this by 3 to calculate beats per minute (heart rate).

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