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

Investigating the density of blood

Extracts from this document...

Introduction

Investigating the density of blood Introduction I will investigate the relative density of three unknown blood samples by measuring the time taken for drops of simulated blood to fall under gravity through a solution of copper II sulphate. By comparing the two samples I can determine the relative density of them compared to the normal sample. There are three separate samples of simulated blood and each one will be tested. 1. Sample 1 will be from a healthy male 2. Sample 2 will be from the same male after 6 months of regular exercise. 3. Sample 3 will be from the same male after suspected blood doping. By analysing the results obtained I should be able to determine the relative density of the blood. Background scientific knowledge and understanding I would expect an average healthy male to contain 5-7 litres of blood. Each drop of blood would contain * 250 million red blood cells * 400,000 white blood cells * and 15 million platelets [JA1]1 Located with the erythrocytes is haemoglobin. Haemoglobin transports oxygen which is used for respiration. The red blood cells transport the haemoglobin so it can be delivered to wherever needed inside the body, however haemoglobin has a relatively small weight for a respiratory pigment. Haemoglobin molecules are able to pick up oxygen where it is plentiful and transport and release it to where energy levels are low in the body. This is important when exercising or playing a sport when you require a lot of extra oxygen. As cells in tissues are respiring more when exercising they are using up more oxygen, this means the concentration of oxygen in these areas will be low. To continue performing well they require more oxygen. The oxygen in the haemoglobin will now find its way to the tissue and will diffuse from the red blood cell, this method keeps a relatively good consistent supply of oxygen. ...read more.

Middle

Avoid splashing and contact with eyes and mouth. There is a risk of broken glass if beakers and measuring cylinders are not handled correctly leading to cuts. Handle carefully. [JA6]6 Results My raw data is located in the appendix of my coursework, my processed results are shown below. Blood drop number Sample 1 /s Sample 2 /s Sample 3 /s 1 8.79 7.33 6.03 2 13.44 10.42 5.84 3 9 6.63 6.57 4 8.75 7.62 5.87 5 8.66 9.33 6.26 6 9.36 6.69 6.9 7 14.02 6.88 5.74 8 9.34 8.12 7.69 9 12.36 10.39 6.31 10 8.79 6.98 7.66 Mean 10.251 8.039 6.487 Standard deviation (2 dp) 2.14 1.48 0.72 Standard error 10.25 +/- 1.55 8.03 +/- 1.07 6.49 +/- 0.51 True mean (95%) confidence 8.60 - 11.80 6.96 - 9.10 5.98 - 7.00 Relative densities To compare densities I will assume the relative density of the normal sample is 1.00 The relative density of unknown sample is found by formula, RDsample1 x time sample 1 / time unknown sample. RD sample 1 = 1.00 x 10.25 / 8.03 = 1.28 (28% increase in density over sample 1) RD sample 2 = 1.00 x 10.25 / 6.49 = 1.58 (58% increase in density over sample 1) Tally chart A tally chart helps to decide if the data is normally distributed by plotting a frequency histogram using the chart. The intervals help to show how compact the data is, they are found by dividing the difference between the maximum and minimum values by ten. I have rounded the intervals to the nearest tenth. Key: | represents a count of one / represents a count of five. Speed of drop /s (seconds) Sample 1 total 7.50-8.00<= 8.00-8.50<= 8.50-9.00<= / 5 9.00-10.00<= || 2 10.00-11.00<= 11.50-12.00<= 12.00-12.50<= | 1 12.50-13.00<= 13.00-13.50<= | 1 13.50-14.00<= 14.00-14.50<= | 1 Maximum value 14.02 Minimum value 8.66 Difference = 5.36 Intervals = 5.36 / 10 = 0.536 = 0.5cm intervals Speed of drop /s (seconds) ...read more.

Conclusion

This would eliminate a factor which increases the time taken to travel the distance and would make my results more accurate. > Using a Pasteur pipette means it is very tricky to produce a constant volume of blood droplet. By using a different piece of apparatus it would have been easier to make droplets the same volume. Having the same size droplets eliminates this variable and means my results would be more accurate. An ideal tool for getting a constant volume of the blood would be an automated pipette. > It would have been possible to reduce the parallax error if I had been able to use somebody to stay seated and time the blood droplet to travel the total distance. This person would be dedicated to timing the blood droplet and would not have to worry about releasing the blood droplet. They would just been doing the timing and therefore it is likely that they would have timed more accurately because they would become accustom to where to position themselves to reduce parallax error and because all they would have to do is time the droplet their reaction times would be minimal. > Using the same pipette for every solution means that when you wash the pipette out water stays in the pipette and this dilutes the blood sample when it is taken up. Diluting the blood sample affects the relative density of the blood sample and therefore to avoid this problem in the future I would have used a new pipette for every drop of blood. Validity of conclusion The true means of my samples show some overlap. Blood drop number Sample 1 Sample 2 Sample 3 True mean (95%) confidence 8.60 - 11.80 6.96 - 9.10 5.98 - 7.00 This would suggest that the data is not as valid as it could have been. I think that performing at least 20 measurements for each sample would help to validate my conclusion. ...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)

    There can also be nasty side effects. * Some drugs are legal and used for recreation e.g. caffeine, nicotine, alcohol. They can be called social drugs. Some athletes take performance enhancing drugs such anabolic steroids. These can have bad side effects e.g.

  2. Marked by a teacher

    Biology notes

    5 star(s)

    from simple inorganic chemicals (carbon dioxide and water) using light energy. More detail: * Light energy is absorbed by a green substance called chlorophyll. * Plants look green because chlorophyll reflects green wavelengths of light. * The plant then uses this energy for photosynthesis. * Light energy is used to convert carbon dioxide and water into sugar (glucose).

  1. Marked by a teacher

    Investigate the effect of altitude training on the density of blood.

    4 star(s)

    Cooperative binding is the characteristic of haemoglobin to have a greater ability to bind oxygen after a subunit has bound oxygen. Thus, haemoglobin is most attracted to oxygen when three of the four-polypeptide chains are bound to oxygen. Below is the oxygen dissociation curve, it shows the partial pressure of

  2. Human biology short notes

    the trachea and bronchi from collapsing during inspiration * Trachea divides to two main branches- Bronchi (Bronchus) * The two bronchi divide further to Bronchioles * Bronchioles divide into tiny air sacs- Alveoli (Alveolus) * The left side of the lung has two lobes and the right side has 3

  1. Should the cloning of humans be allowed?

    Likewise, female animals are put in more danger as their eggs are surgically removed from them. Though they are put under anaesthesia, they still experience some pain.1 In relation to human cloning, if it ever became possible, something similar to this may occur because lots of eggs would need to

  2. Blood Doping

    Blood doping refers to enhancing performance through providing extra red blood cells to the body so that more oxygen can be processed.

  1. Stem Cell Research

    For example the cardiac muscles, in the heart could be cultivated from stem cells, and then introduced into a patient to replace damaged ones. This could prevent heart disease and possibly even strokes. Diabetes could even be treated, through the production of pancreatic cells, which will increase insulin levels, thus decreasing symptoms of diabetes.

  2. Diabetes Type 1 and 2

    Big vats of bacteria now make tons of human insulin, so this can make pure human insulin. This is called genetic engineering. Until the 1980s, all insulin was extracted from the pancreases of cattle and pigs. The sequence of amino acids (the building blocks that make up the protein)

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