Preliminary Investigation:
In the preliminary investigation I will be conducting an experiment to determine on how long to run the main investigation for.
Preliminary Apparatus and Diagram:
1. Test tube
2. Test tube rack
3. Bung
4. Rubber Tube
5. Potato
6. Beaker
Preliminary Method:
1. Place 2mm of H2O2 into a test tube.
2. Collect a piece of potato and use a cork borer to produce a tube of potato. Cut it 1mm long and place into the test tube along with the H2O2.
3.Add 2ml of washing up liquid to the test tube.
4. Start the clock.
5. Record the amount of bubbles that are being produced by the reaction in a suitable form.
Preliminary Results:
Preliminary Conclusion:
The results obviously differ and so there must be something wrong with the equipment or set up of the equipment. This has indicated to me that I need to be more thorough when checking the equipment before the experiment. It could also be that I need to be more accurate with the amount of chemicals, making sure the same amount goes in each experiment. It would be an unfair test otherwise. But as for the aim of the preliminary investigation the amount of time, I feel is to long and so in the actual experiment I will be conducting each experiment for 10 minutes instead of 20 minutes because plenty of results could still be obtained within 10 minutes.
Main Investigation:
Apparatus Set up and List:
1. Adjustable water bath
2. Test Tube
3. Bung
4. Rubber Tube
5. H2O2
6. Potato
7. Washing up liquid
8. Beaker
9. Ice
10. Thermometer
Fair test:
The things that are going to stay the same will be the amount or size of the potato used the amount of H202, washing up liquid. These are called the non-variables. The one factor that will change will be the temperature of which the reaction will be taking place in and this is called the variable. The temperatures will be conducted at 5oc, 25oc (Room Temperature), 50oc and 70oc.
Safety:
I will be using a water bath on two of the higher temperatures so I must be aware that it is an electrical appliance and not have the water bath at a very high temperature. H202 is an irritant so goggles must be worn when transferring the chemical from one spot to another. A potato must be cut to a suitable length using a cork borer and a scalpel. When the scalpel is in use it must be used with a ceramic tile and care must be taken.
Method:
1. Collect a test tube and add 2 ml of H2O2 and 2ml of washing up liquid.
2. Collect a large beaker and place ice and water into it until it reaches 05oc degrees.
3. Place one end of the rubber tube into a bung and the other end into a beaker of normal water.
4. Now cut the potato buy creating a cylinder shape and pushing the cork borer through the potato. Now place the potato onto a ceramic tile and measure 1mm of potato, cut it at this point.
5. Drop the piece of potato into the test tube and immediately place the bung into the test tube.
6. Start the stop clock and place the test tube into the ice and water beaker.
7. Monitor the ice and water beaker using a thermometer and adding more ice when at a constant 05oc by adding more ice when needs making sure it.
8. Do the same but place the test tube into a water bath and carry out the experiment at the different temperatures
9. Each experiment with a different temperature needs to be carried out 3 times to be able to create an average and conclude a better result.
Results:
Table of results at temperature 05 oc Degrees.
Table of Results at 25 oc Degrees (Room Temperature).
Table of Results at 50 oc Degrees.
Table of Results at 70 oc Degrees.
Line Graphs to show data results:
Conclusion:
The results show that there is an obvious difference in the amount of bubbles produced when the temperature differs. In the 25-degrees experiment, this is where the amount of bubbles reaches its peak throughout the other experiments at different temperatures. The least amount of bubbles, at the end of the time limit was in the 05-degree experiment where it reached an average of only 4.3 bubbles for the 10-minute period. The 50 and 70-degree experiments have roughly the same amount of bubbles produced on average but differ through out the experiment. The 50-degree experiment gives of a lot of gas to begin with but during the experiment the amount of bubbles given off starts to slow down. The 70 degree experiment doesn’t have as faster start as the 50 degree but catches up around 5 minutes into it and they both end up with roughly the same amount of gas given off eventually.
There doesn’t seem to be any trends or patterns in the different experiments but there is a set of anomalous results and this is in the 70-degree experiment. In this case the unexpected results can be explained and that is was the fact that the test tube in use was broken and so the gas was leaking and not producing any results. I did not take note of my preliminary results and conclusion and so this is why this part of the experiment went wrong.
Evaluation:
The results have proven that the enzymes seemed to work best in the 25 oc (Room Temperature) experiment. The reason for this is probably the fact that the enzymes work at their peak at this temperature because they are used to it and have evolved to it.
My hypothesis is supported by the results in one way but not for the reason I have given. I stated that temperature will effect the rate of the reaction but because of the collision theory but this was not that case because the enzymes worked best at a lower temperature than higher ones.
The only problem with the experiment was that one of the test tubes was broken. I don’t know if this happened during experiment or was broken to begin with but I suspect it happened during the experiment because it happened while conducting the higher temperature experiment at 70 oc degrees. I feel that the method was fine and that could not be improved.
I think the experiment could be improved by increasing the accuracy of the different solutions when I placed them into the test tube. I used syringes to place the washing up liquid and H2O2 into the test tube. It worked fine with the H202 but the washing up liquid was too viscous and so it was difficult to be accurate when transferring it from the beaker to the test tube. To improve the experiment even more I would check all the equipment thoroughly before starting it. Overall I found that the experiment went well and only a few areas of it could be improved.
