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

Biology investigation - investigating the relationship between the breathing rate and the carbon dioxide concentration of exhaled air

Extracts from this document...


James Fung 18thJanuary,2002 Biology investigation - investigating the relationship between the breathing rate and the carbon dioxide concentration of exhaled air Result: Breathing rate (Breathes per minutes) A B C D E Resting 12 14 8 12 15 2 minutes exercise 25 20 18 22 25 3 minutes rest 14 10 15 19 16 6 minutes rest 13 5 9 17 15 Carbon dioxide concentration (Carbon dioxide %) A B C D E Resting 19% 3.9% 8.1% 40.8% 6% 2 minutes exercise 20% 3.2% 8.3% 100% 31% 3 minutes rest 2.5% 13.9% 4.8% 47.3% 12% 6 minutes rest 6.3% 2.1% 3.5% 77.3% 9% Fig.2 Analysis: For those 5 sets of data I have got, I have drawn them up on Fig.1. Then I have chosen the one from person E to analyse further, which gives Fig.2. There are some chemoreceptors, which are situated in the medulla of the brain, the arch of the aorta and in the wall of the carotid arteries. And they are stimulated when there is an increase in carbon dioxide level inside our body. ...read more.


But because we were holding the test tube with our hand, the warmth from our hand might have made the concentration of carbon dioxide to reduce. 2) Sample collecting --- when collecting the expired air, we were not meant to collect the air, which first came out, because this air is from the trachea, so there wouldn't be any gas exchange happened to this air. If the gas collected hasn't be diffused in the lung, the concentration of carbon dioxide would almost be the same as the air we breathed in. Results, which are affected, would possibly be A & C. This is because the carbon dioxide concentrations of person A & C at resting and after 2 minutes exercise were nearly the same. 3) Time --- there was water inside the tube when we carried out the second part of the experiment, which was to find out the carbon dioxide concentration. This was due to those test tubes have been left for few days after the air has been collected because we didn't have enough time to finish it in the same day. ...read more.


Besides, person D's result is awkward compare with the others because the concentration of carbon dioxide at different times are extremely high especially the one after 2 minutes exercise, she had 100% carbon dioxide concentration. If I have a chance to do this experiment again, I would do it better by improving the possible errors I have mentioned. Improvements to the respective errors like: 1) The effect of heat when handling the equipment --- in order to reduce the warmth from the hand into the tube, I would hold the tube with a test tube holder instead of my hand 2) Sample collecting --- not to collect gas that I breathe out first because there is no gas exchange to these gas 3) Time --- try to finish the whole experiment in the same laboratory with almost the same temperature in one day and repeat the experiment for a few times to get an average result 4) The depth of breathing --- try to ask everyone to take a depth breath before blowing out the gas collected 5) Potassium hydroxide used --- try not to use cold potassium hydroxide The end ...read more.

The above preview is unformatted text

This student written piece of work is one of many that can be found in our GCSE Humans as Organisms 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 GCSE Humans as Organisms essays

  1. Marked by a teacher

    Biology Revision notes - Human Biology

    5 star(s)

    This decreases the oxygen carrying capacity in the blood. Less oxygen is delivered to the tissues, leading to heart disease because the heart has to work harder. Nicotine is a stimulant. It makes the blood vessels narrower. It increases blood pressure and puts strain on the heart. It increases the risk of a stroke and a heart attack.

  2. Human biology short notes

    Immune System Immunity * Is the resistance provided by the body against harmful microorganisms * Before symptoms appear * But the patient does not develop the disease Innate Immunity * Is the inbuilt immunity provided by the body since birth Acquired Immunity * Is the immunity gained after birth where

  1. Experiment to compare oxygen and carbon dioxide content of inhaled and exhaled air

    Put some tap water into a water trough b. Fill full tap water into a jar c. Cover the jar and reverse d. Put the jar into the water trough e.

  2. Potato and Osmosis Investigation

    My preliminary sugar solutions were not accurate as the ratios on which they were mixed was not accurate. So the next experiment, I will use the help of my science teacher. Final Method Below I have made a table to show how the concentrations were mixed.

  1. The effect of exercise on gas exchange and breathing

    These then divide again 22 times until the alveoli are reached. The alveoli are microscopic blind-ended sacs and are the site of gas exchange between the atmospheric air and blood. There are around 3-6 x 108 alveoli in the lungs and each alveolus is made up of a single layer of epithelium.

  2. Daphnia Investigation

    The reason why I think this is because the more ethanol and caffeine you use the more affect it may have on the nervous system. Variables: There are a number of variables in my experiment that if was changed would vary the results.

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