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An investigation into the density of 'mock blood'

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Chris Ellison An investigation into the density of 'mock blood' Sample A - blood taken from a normal healthy adult male who lives at sea level. Sample B - blood taken from the same male after six months of aerobic exercise. Sample C - blood taken from the same male after training for three months at altitude. Results Time taken for a drop of the sample to fall through 100cm3 of Copper (II) Sulphate Solution. Sample A (Seconds) Sample B (Seconds) Sample C (Seconds) 11.5 12.0 10.0 11.5 13.0 8.0 14.5 12.0 10.0 14.0 12.0 7.5 12.0 13.5 10.0 12.5 14.0 11.0 14.0 16.0 7.0 12.5 12.0 8.5 16.5 14.5 9.5 12.0 11.5 7.5 Mean 13.10 Mean 13.05 Mean 8.5 Now I am going to carry out some statistics on my results to find if they occurred by chance or not. I am going to use the t-test because I need to compare two sets of results that I collected. T-test tables Sample A x x-x (x-x)2 11.5 1.60 2.56 11.5 1.60 2.56 14.5 1.40 1.96 14.0 0.90 0.81 12.0 1.10 1.21 12.5 0.60 0.36 14.0 0.90 0.81 12.5 0.60 0.36 16.5 3.40 11.56 12.0 1.10 1.21 x = 13.10 ? ...read more.


It also means that is a greater than 0.1 chance that it occurred by chance. This makes sense as my research showed me that aerobic exercise only affects the heart and muscles not the density of the blood. Sample A compared with Sample C The P value for this t-test however is very different. The value was P<0.001, this means there is a difference and that this out come was not reached by chance. If you did this test again the same result would occur 99.9% of the time. Training at altitude can change the density of the blood. The kidney keeps a constant check on the oxygen in the blood as part of homeostasis and when they are low because you are at altitude a hormone is released. This hormone tells the bone marrow to produce more red blood cells. The more red blood cells in your blood the more dense it is and this showed up in our tests. Evaluation I believe that the experiment was accurate enough for the results needed to do our coursework. ...read more.


We used a stopwatch operated by us at eye level with the measuring cylinder. The size of the drop could not be measured either which meant we had variations in that too. The size of the drop would affect the surface area and therefore friction acting upon it; this would slow down the droplet. The shape that was usually a doughnut shape could also change. These are all reasons for my results to be anomalous. To counter some of these problems we could use other equipment or methods. We could use a light gate that works by detecting a break in a beam of light caused by a blob of mock blood falling through the solution. This would greatly improve the accuracy of the results, as would having two people to record and time the results. The main sources of error in the experiment were mainly human error in the fact that the person carrying out the experiment controlled the drop size and timing. Most of the time there weren't any problems with our techniques but errors were still made. ...read more.

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