An Investigation Into the Density of Mock Blood Essay Example

An Investigation Into the Density of Mock Blood Essay Example An Investigation Into the Density of Mock Blood Essay An Investigation Into the Density of Mock Blood Essay Essay Topic: There Will Be Blood INTRODUCTION The aim of this investigation is to find out the relative densities of three different mock blood samples representing three different people. Sample A represents blood taken from a normal, healthy adult male who lives at sea level. Sample B represents blood taken from the same male after he has undergone six months of regular aerobic exercise. Sample C represents blood taken from the same male after he has spent three months undergoing aerobic training at altitude. PREDICTION I predict that the density of sample A and B will be fairly similar with not a lot of difference between them. However, there will be a difference between samples A and B compared to sample C. APPARATUS * 100cm3 sample A * 100cm3 sample B * 100cm3 sample C * 24.96g copper (II) sulphate * 1dm3 distilled water * three 1cm3 plastic syringes fitted with long needles * three 100cm3 measuring cylinders * stopwatch or clock METHOD 1. Fill three measuring cylinders with a 0.1mol/dm3 copper (II) sulphate solution, to a depth of approximately 5cm above the 100cm3 level. The copper (II) sulphate solution should be made up by dissolving 24.96g of copper (II) sulphate into 1dm3 of water. NB this must be done accurately. 2. Introduce some blood into one of the syringes, fitted with a long needle. 3. Place the tip of the needle just above the surface of the copper (II) sulphate solution. Gently press the plunger on the syringe to release a small drop of the blood into the copper (II) sulphate solution. 4. Record the time taken for the drop to fall between the 100cm3 and 10cm3 marks. 5. Repeat the procedure to obtain TEN readings. 6. Carry out this procedure for the two other blood samples. 7. Record results in a suitable format. RESULTS SAMPLE READINGS (time taken to fall in seconds) 1 2 3 4 5 6 7 8 9 10 A 11.78 11.54 12.22 12.25 11.87 11.04 11.90 11.22 12.13 11.62 B 12.41 13.19 12.75 12.07 12.53 13.81 12.22 12.50 12.53 13.03 C 8.59 9.34 8.97 8.35 8.88 8.44 8.62 9.02 8.56 8.94 Averages: A = 11.75secs B = 12.70secs C = 8.77secs To help me make a comparison between the samples I worked out values of t for the difference between A and B, then the difference between A and C. Then I used the students t Distribution to see what percentage of my values lie outside the range -t to +t . (These calculations are on the separate sheets provided). CONCLUSION I believe my results prove that my prediction is correct. Samples A and B are relatively similar, if you compare the means, for example, the mean for sample A is 11.75 seconds and the mean for sample B is 12.70 seconds. These are fairly similar. Especially when in comparison to sample C, for which the mean was 8.77 seconds. These results show that the blood in sample C is denser than the blood in samples A and B. This is due to the structure of the blood in each sample. An investigation into the density of mock blood Essay Example An investigation into the density of mock blood Essay An investigation into the density of mock blood Essay Essay Topic: There Will Be Blood An investigation into the density of mock bloodSample 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.ResultsTime 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)11.512.010.011.513.08.014.512.010.014.012.07.512.013.510.012.514.011.014.016.07.012.512.08.516.514.59.512.011.57.5Mean 13.10Mean 13.05Mean 8.5Now 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 tablesSample Axx-x(x-x)211.51.602.5611.51.602.5614.51.401.9614.00.900.8112.01.101.2112.50.600.3614.00.900.8112.50.600.3616.53.4011.5612.01.101.21x = 13.10? = 23.4Sample Bxx-x(x-x)212.01.051.1013.00.050.3012.01.051.1012 .01.051.1013.50.450.2014.01.051.1016.02.958.7012.01.051.1014.51.452.1011.51.452.10x = 13.05? = 18.63Sample Cxx-x(x-x)210.01.101.218.00.903.6110.01.101.217.51.401.9610.01.101.2111.02.104.417.01.903.618.50.401.969.50.600.367.51.401.96x = 8.5? = 21.52T-testsSample A compared to Sample BDegrees of Freedom = 18Variance (S2) = S2A= 2.60S2B= 2.07Sample A compared with Sample CDegrees of Freedom = 18Variance (S2) = S2A= 2.60S2B= 2.40Analysis of t-testSample A compared to Sample BThe P value for this t-test was P 0.1 (P was greater than 0.1). The value means that there is not much difference between the times taken for sample A and sample B. 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 CThe P value for this t-test however is very different. The value was P0.001, this means there is a difference and that th is 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.EvaluationI believe that the experiment was accurate enough for the results needed to do our coursework.There were however some anomalous results, in the test for sample A there was a result of 16.5, which is a full, two and a half seconds slower than the other results. Also in the test of sample B there is a 16 second result that is also much larger than the others.There were quite a few sources of error in the experiment. Each time the experiment was repeated the droplet changed size. The timing of the experiment was also hard to judge even at eye level, this did have adverse effects on the results as we cant know if the results are correct. After about 5 repeats of the experiment the Copper (II) Sulphate solution became full of floating blobs of mock blood, this meant that the last 5 tests of each sample could be affected by them. The recording of the time taken for the sample to fall through the Copper (II) Sulphate solution was not at all accurate. It was fine for our needs but relied heavily on our reaction to seeing the droplet pass the start and finish marks. 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 s ome 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 werent any problems with our techniques but errors were still made.