APPARATUS
I will make sure that I have all the equipment that I will need to conduct the experiment safely and fairly, these are goggles, a tripod, a gauze, a heat mat, a Bunsen burner, a heat proof beaker, 14 test tubes (minimum size 10 ml), matches, a thermometer, a stopwatch, tongs, ice cubes, a beaker of marvel milk, a beaker of Trypsin, a pen and paper, 2 syringes (minimum size 5ml), and finally a source of cool water.
PLAN
When about to conduct the experiment, my first step will be to make sure that the area around me and anywhere I may need to go is safe, by checking that bags and stools are out of the way, and the desk where the experiment is to be conducted is clear. My first step will be to make a control to compare my real results with, this will be hydrochloric acid. Then I will add water to a heat proof beaker, use the thermometer to read the temperature, and add ice or heat with a Bunsen burner to get the temperature to 15°C, when it reaches the temperature I will start the stopwatch, and keep the temperature constant for 2 minutes. After 2 minutes of keeping the beaker at a constant temperature, I will use a syringe to acquire 5ml of Trypsin, then a different syringe to acquire 5ml of milk, then put the substances into separate test tubes, as it is important they do not react at a different temperature, the next step is to put the test tubes into the beaker, which will be acting as a water bath, whilst keeping the beaker at the correct temperature (in this case 15°C). I will then keep the temperature constant with the 2 test tubes in the beaker for 2 minutes, after that time I will mix the Trypsin with the milk, start the stopwatch and record the time when the substance becomes as clear as the control. If the reaction appears to be not happening, or very slow, I will wait for 5 minutes, after that if it has not happened it will be classed as no reaction. I will do the experiment for 6 other temperatures; 25°C, 35°C, 45°C, 55°C, 65°C and 75°C. I will repeat the whole experiment 3 times, as it appears to be quite easy to get highly varying results.
RESULTS
FIRST EXPERIMENT
SECOND EXPERIMENT
THIRD EXPERIMENT
AVERAGES OF ALL 3 EXPERIMENTS
ANALYSIS OF RESULTS
From these results, one can see that there is a trend, longer times at the lower temperatures, 15°C took the longest time with 106.14 seconds on average, the quickest times at 55°C, with an average of just 14.33 seconds, and at the higher end of the temperatures, medium times, 75°C getting 29.74 seconds. Lower temperatures taking a long time is no surprise, my prediction matches this in saying that due to the lock and key theory in which it states that enzymes will be deformed under certain conditions, in this case temperature, thus stopping them from “fitting” with the molecule, there will be few Trypsin enzymes left, therefore taking a longer time. The quickest times are at 55°C, which is a slight surprise as the human body is not usually that hot, therefore I would have expected that the optimum temperature would be closer to 45°C. Yet, by far the biggest anomaly, is that the Trypsin enzymes are still getting quick reaction times at 75°C, this is exceptionally unusual, I predicted that the reaction times would either be very slow or over the 5 minute time limit, therefore counting as no reaction. The reason for this may be a faulty batch of Trypsin, as other schools in the area also report getting incredibly quick times at the higher temperatures. Less likely is that it is a human mistake by the person conducting the experiment, me, I think this is less likely as after doing the test 3 times, the results were all roughly the same, and it is almost impossible that I started the stopwatch minutes late and stopped it very early. Apart from that extraordinary anomaly my prediction matches my results.
EVALUATION
I think that this experiment was conducted in a methodical, scientific and precise manner, the anomaly is incredible and extremely unlikely to have been caused by poor experimenting. This is a difficult experiment to conduct as it is very hard to start the stopwatch, pour the mixture, compare to the control, and keep the temperature constant all at the same time. It is also questionable how one would decide that the mixture is exactly the same as the control, all of these factors together could lead to widely varying results. To make this experiment more reliable, and therefore get better results, more than one person should do it, so as one is pouring the mixture, one could start the stopwatch, and even one more person to keep the temperature constant would be acceptable, with regards to the mixture being exactly the same as the control, possibly a computer would be able to do such a task. My plan was fully successful, I did not change any of it.