Through out the experiment I will take safety precautions in wearing safety goggles and being careful of the hot water and any other hazards around me.
My experiment will be a fair test because I am keeping the yeast the same amount through out and the Hydrogen Peroxide the same to make it fair. The only variable I will change is the temperature, and I will do this using a thermometer to get to my required temperature. In my preliminary experiment I left 15 sec before checking the height of the froth, I have used this as my guideline for seeing how long I would leave it. I am happy looking back on my preliminary results that 15 seconds should be long enough.
Prediction
I predict that the enzymes will work best at higher temperatures causing the height of froth to increase. I know this from looking back at my research. When enzymes are heated it gives them energy, this energy causes them to move (higher the temp the faster they move the lower the temp the slower they move) and collide with other molecules causing a chemical reaction. Although enzymes work best at high temperatures there is a cut of point. According to my research enzymes work best up too 40°C/50°C any temperature after this the enzymes denature and slow down causing the height of the froth to decrease. When doing my experiment I have to take into consideration that the heat will escape through the beaker and I will loose about 7°C. So it is possible that the enzymes might work at 50°C
Results
These results did not entirely work out as I had predicted. When making my prediction I used my scientific research, which said that enzymes work best at around 40°C/50°C but also worked at higher temperature e.g. 60°C as well. Now I am going to do three more temperatures to see whether enzymes carry on working at very high temperatures and see if the height of the froth still increases.
Here are my results for temperatures, 70°C, 80°C and 90°C. I have found that although originally my prediction was wrong, that enzymes stop working at higher temperatures. In a matter of speaking they do but not at the temperatures I originally said. Although the enzymes didn’t stop working at 40°C like it said in my research, they did slow down and start to denature at very high temperatures (e.g. 70°C and above) and the froth decrease in height.
Analyse
My results show a clear indication that as temperatures increase (to a certain temp) the froth decreases in height.
That certain temperature was 60°C. But in my investigation after 60°C the height of froth began to decrease. The height of froth reached it’s peak around 60°C. My graph shows an increase in height and then after 60°C decreasing in height. From my preliminary research I now know that reactions occur differently and different temperatures. For example at lower temperatures the reaction of froth is slow. This is due to the fact that enzymes collide at higher temperatures causing a greater chemical reaction. Enzymes at the higher temperatures collide more often than where there at low temperatures as high temperatures give the enzymes more energy. Although they work at best at high temperatures there is a cut of point (for example in my investigation it was 60°C) and very high temperatures can cause the enzymes to loose energy and denature. Causing the chemical reaction to be slowed down causing very little froth or none at all.
Evaluation
My experiment was interesting and I really enjoyed the experiment. The thing I found difficult was to get to a specific temperature and keep it at that temperature for a certain amount of time, with out it loosing heat and dropping in temperature. This may have been the reason why some of the results did not follow my preliminary results and my research. My research shows that most enzymes die and slow down after 40°C/50°C. But my results show that enzymes carry on working up to 60°C. This might have been because the water bath inside the beaker was reading 60°C. But because there is another layer of glass within the beaker the test tube, the hydrogen Peroxide and yeast may be 10°C or so less than what I thought it was actually at.
In my opinion my evidence is not entirely good evidence and therefore might not be reliable, some of the results are not in the range of previous results e.g. 60°C.
To improve my results if I were to do it again, I would make sure that most of the heat from the beaker could not escape as easy so that it would keep and sustain the specific temperature for longer. Another thing I would change is rather than wait 15 seconds wait longer allowing the two substances to create a bigger or less chemical reaction. The final thing I would change is to have temperature still as a variable but have more temperatures. Not just 20°C, 30°C, 40°C…. but 20°C, 25°C, 30°C, 35°C, 40°C…
Although 60°C was much higher than what I had expected my graph near enough matches the graph in my research.
Page James Baron
Candidate Number: 8007
