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

How caffeine affects Daphnia heartbeat?

Extracts from this document...

Introduction

An experiment to determine how caffeine affects the heart rate of Daphnia (water fleas)? Introduction The purpose of this experiment is to determine whether or not caffeine has an affect on the heart rate of Daphnia Hypothesis The Daphnia heart rate will increase with the concentration of caffeine. I based my hypothesis on the fact that humans heart rates increase with caffeine as it acts as a stimulant drug. In the experiment there will be several variables that I need to try and control, the temperature of the water is one of these because if the temperature is higher or lower on the day the results may end up being higher or lower, this would make my results inaccurate. I need to try and limit the human error in the experiment as the daphnia heartbeat is very quick so it will be hard to be completely accurate so we are using the "blind method". We need to use the same microscope throughout testing as others may have different strength lenses. I am also going to keep the species of daphnia the same, as different species may react differently to the caffeine. I will use the same type of caffeine and record the amount of time the daphnia spend in the caffeine before the counting begins, and try to keep this to a similar range. ...read more.

Middle

Equipment * Culture of Daphnia * Cavity slides * Dropping pipettes * Distilled water * Caffeine solution of different concentrations * Cotton wool * Stop clock * Microscope * Beakers Method 1. Get all the equipment as shown above 2. Place a few strands of cotton wool on a cavity slide, this restricts the movement of the daphnia 3. Add a couple of drops of distilled water to the slide 4. Use the microscope to look at the daphnia's heart beat 5. Use a stopwatch to record the number of heartbeats per 15 seconds 6. It is easiest to tap a pencil on a piece of paper and count up the pencil marks at the end and times this number by 4 to get results for 1 minute 7. It is best to use a "blind method", where the person who is counting is unaware of which solution has caffeine 8. Repeat the procedure using other daphnia and use several different concentrations of caffeine 9. Repeat each concentration 3 times for accuracy 10. Get the average heartbeat for each concentration Safety * Wear safety goggles * Wear lab coats * Wash hands at end of experiment as we have been dealing with living organisms Fair Test To make it a fair test we will ...read more.

Conclusion

Also this group has not included the results for 0.5 making the data pointless. The group labelled also seems to have 2 inaccurate results at distilled water and 0.5% caffeine so I would also class these as anomalies. Therefore this leaves us with just two sets of results. This means that we need to collect more data for us to be able to get an idea of accurate readings. Evaluation If I were to do the experiment again I would find a more accurate way of counting the heartbeats as they ended up being very fast. One way I could do this would be to use videoing microscope to record the daphnia heartbeat then use a computer program to slow the heartbeat down so I could count it accurately. I could also do more trials to make the readings even more accurate. I would try using Different types of caffeine such as decaf and also try using a different species of daphnia and even see if temperature had an effect. I would also try to do many more different concentrations of caffeine. As I know from my knowledge caffeine is a stimulant so I could experiment using a depressant such as alcohol and see how this affects the daphnia. ?? ?? ?? ?? ...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

Here's what a teacher thought of this essay

4 star(s)

****
A good account of the investigation but a little more attention to detail would have improved it.

Marked by teacher Adam Roberts 26/06/2013

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 temperature on the rate of respiration in yeast

    5 star(s)

    This results in the chain of carbon by producing a a-ketoglutarate. This also diffuses carbon dioxide and produces reduced NAD. Then this converts into 4 carbon chain of succincyl coenzyme which then changes into succinate and then this releases energy compound such as FADH.

  2. Marked by a teacher

    The Role of the Respiratory and Circulatory Systems in the Provision of Oxygen and ...

    3 star(s)

    and tunica externa (the outer layer composed of connective tissue). Arteries pulse blood rapidly through the body under high pressure due to a relatively small lumen and their composition of thick muscular walls and plentiful amounts of elastic tissue. These arteries then branch into smaller arterioles and then into even smaller capillaries.

  1. Cycles in Biology.

    A means to control this problem became a paramount need. Testing concluded that phosphorus was the key nutrient for the control of eutropication. There are a number of cycles that take place in humans. The menstrual cycle is a cycle that only occurs in females.

  2. The effect of temperature on hatching effect of brine shrimps

    The 17�C results were very low with a maximum of 2 shrimp in the most successful trial, trial 2. This supports my hypothesis of "This higher temperature is what I believe to be the most suitable temperature for the shrimps.

  1. An investigation into the effects of temperature on the rate of anaerobic respiration of ...

    Therefore yeast can not respire anymore. A diagram showing the growth curve at various stages Initially, the yeast solution respired aerobically; this gives off the highest yield of Co2 as the pyruvic acid molecules are completely broken down into carbon dioxide and more energy, thus the gradients for each reaction of the yeast solution in a

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

    After the concentration of ethanol reaches 12%, the yeast is killed and fermentation stops. The Lock & Key Theory Emil Fischer originated the lock and key theory in 1894. It states that it takes the correct key to open a lock.

  1. Vitamin C Practical Experiment Write Up

    Safety; Take care of glassware. Sanitise experimental area after. Wear eye protection at all times.. Care when handling juice samples or chemicals as they may stain. Do not drink juice samples as dangerous chemicals may be present after experimentation. Pre-Experiment Method; The method I will be conducting is simple.

  2. The Effect of Caffeine on Daphnia Heart Rate

    My results showed a positive correlation between the concentration percentage of caffeine and the heart rate of the Daphnia. The causation of this is the caffeine percentage increase. My result at 0.2% is slightly out of the line of best fit however still indicating a positive correlation.

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