Preliminary Work: I have done some Preliminary work before I have collected my actual results. To make sure my final experiment is correct and I cannot do it any better I have done a test run. I followed my method for 1 fuel. I chose ethanol. I ran this experiment 1 minute and only did one run of the experiment. The results showed very little temperature increase, because I used the fuel that burns least effectively. Also in this experiment it was a big possibility that I would get an anomaly because I could not test it against anything else. I have decided to test each fuel 3 times so I can produce averages for all of the fuels and reduce the affect of such anomalies because I will be able to clearly notice them. I have also decided that 1 minute is not long enough, so I chose to do a 2 minute trial. I have also increased the amount of water in the calorimeter because I think that 50ml is not enough I have chosen to do 100ml.
Apparatus:
- Ethanol
Propanol
- Butanol
- Pentanol
- Hexanol
- Heptanol
- Octanol
- Calorimeter
- Clamp Stand
- Thermometer
- Scales
- Measuring Tube
Diagram of Set-Up:
Method: First I will set up the experiment as above with the listed equipment. There will be 100ml of water in the calorimeter. Before conducting the experiment the temperature of the water and the weight of the fuel will be measured and recorded. The calorimeter must be 3cm from the wick to the calorimeter and the amount of water must be exact to ensure a fair test. When the equipment is set up the fuel wick will be by Bunsen burner and allowed to burn for 2 minutes. Then the thermometer reading will be taken again and the new weight of the fuel recorded. I will carry this experiment out 3 times for each alcohol allowing me to produce averages.
Fair Test: To make my test is fair I must consider these factors-
- The calorimeter must be 3cm from the wick. This must be done, because different amounts heat will be lost in the atmosphere if the distance id different.
- The equipment used must all be the same so all the experiments take place in identical conditions.
- The amount of water must be exactly 100ml to ensure a fair test- the same amount of water must be used every time because we know that that the mass of water greatly affects the temperature increase.
- The time must always be 2 minutes exactly, because otherwise more fuel will be burnt and the test won't be fair.
- Fuel is the only variable, because It is what I am trying to investigate in my project. . I will use 7 different fuels to give me a wide span of results. Each will be tested three times to improve the accuracy of the results.
Safety: When performing my experiment I must take in to account certain safety rules to make sure the experiment works properly and the experiment is not enhancing the chance of danger on anyone in the nearby vicinity.
- I must make sure that I wear safety glasses at all times to protect my eyes from the naked flame and any boiling water.
- I must not attempt to move or touch the calorimeter or water until I am sure that they have fully cooled down.
- I will tuck away any loose clothing like ties to reduce the risk of fire.
- As with all Science experiments I must keep the aisles clear. In the laboratory I must make sure the aisles, which are not very wide are clear and stray stools or bags could be a potential hazard as tripping over one could cause accidents and spillages. I must be especially careful in this experiment because spillages could be very serious.
Obtaining Evidence
What Results Am I Going To Record?
I will take results of the weights before and after the experiment and use these to work out a difference. I will do the same with temperature. I will record the time, water volume and distance from the flame also which must all be kept constant. These results will be collected 21 times, 3 times for each fuel.
Results Table
A Table Of Temperature against Weight.
I kept the distance from the flame, the water volume and the time constant. The distance from the flame was 3cm, the water volume was 100ml and the time was 2 minutes.
Averages: I have made averages of my results. This will make sure anomalies in some results are less noticeable and will help summarize my results so I can draw graphs. I have worked the average for temperature difference and weight difference because they are the relevant categories.
Energy Production: With the use of the formula “Energy = Mass of water x 4.2 x Rise in Temperature”. I have calculated the amount of heat energy produced in 5 minutes by each of the seven fuels. To do this I used the average temperature difference.
I have also worked out the average energy produced per gram of fuel for each of the seven fuels. To do this I used the average temperature difference and the average weight difference. They are listed in this table:-
From my Background Research if found out the real values for Energy Produced per Gram Of Fuel. They are listed in this table:-
In my experiment: During my experiment I followed a list of rules and precautions to make sure my experiment was safe and also as fair as possible.
To make sure my experiment was safe I:-
- made sure that I wore safety glasses at all times to protect my eyes from the naked flame and any boiling water
- did not attempt to move or touch the calorimeter or water until I was sure that they have both fully cooled down
- I tucked away my tie and any other loose pieces of clothing to reduce the risk of fire.
- As with all Science experiments I kept the aisles clear. In the laboratory I made sure the aisles, which are not very wide were clear and stray stools or bags, which could have been a potential hazard removed because tripping over one could have caused an accident or a spillage. I had to be especially careful in this experiment because spillages could have been very serious.
To make sure my experiment was a fair test I:-
- Made sure that the calorimeter was be 3cm from the wick. This had to be done, because the alcohols would lose different amounts heat in to the atmosphere and the results would be different.
- Made sure the equipment used was all the same so all the experiments take place in identical conditions.
- Made sure the amount of water was exactly 100ml every time because we know that that the mass of water greatly affects the temperature increase.
- The time must always be 2 minutes exactly, because otherwise more fuel will be burnt and the test won't be fair.
- Fuel is the only variable, because It is what I am trying to investigate in my project. I will use 7 different fuels to give me a wide span of results. Each will be tested three times to improve the accuracy of the results.
Analysis Of Evidence
What have I discovered:
Graphs: I have drawn graphs for the Heat Energy Produced (J) Per Gram which I found from my results and from my research. They differ hugely and this is proof of the poor design of the experiment. The graph with my results does not even have any kind of trend, however the actual one does.
Does it match the predictions? My results did not match my predictions because the experiment did not allow me to find as clear trend like I had predicted in my plan. I did not know how inefficient this experiment was going to be when I predicted the results and I relied on scientific knowledge for them.
Conclusions: The conclusions I have drawn are not at all related to any of my results because with my results it is impossible for me to draw conclusions. In a perfect experiment my graphs of heat energy produced per Gram would have a correlation where the more bonds (i.e. Octan-1-ol has the most and ethanol has the least(see alcohol diagrams in plan)) the more heat energy produced per gram. None of my results were suitable, so to conclude I have decided to use scientific theory from my research and I know what should have happened in a better experiment.
Overall I conclude that the more bonds the more heat energy produced per gram. So in a perfect experiment Ethanol would have produced the least energy per gram then Propan-1-ol, then Buthan-1-ol, then Pentan-1-ol, then Hexan-1-ol, then Heptan-1-ol and Octan-1-ol would have produced the most.
Evaluating Evidence
Efficiency / Problems: The experiment was not that efficient because when comparing my results for Energy Produced Per Gram I found that only a few of the results matched. Only Buthan-1-ol and Hexan-1-ol were even close to their real values. This shows massive flaws in the experiment. This is because there are so many opportunities for things to go wrong. We conducted the experiment as accurately as we could, but there were still many anomalies.
Accuracy Of Results: My results in my experiment were not that accurate because the experiment was poorly designed and it was impossible to get results that looked like my researched results. The experiment was too badly made to get any realistic results.
Anomalies: Most results were anomalies and only Buthan-1-ol and Hexan-1-ol were even close to their real values for Energy Produced Per Gram. The rest were miles off and even if you look just at my table and not compare it with the real results you can see it is wrong. Some reasons for anomalies are because energy is lost between the wick and the bottom of the calorimeter and that there was a varying length of wick.
Anomalous results are due to a variety of factors and could not be cut out without a new experiment design.
Results As Evidence Of Conclusion: The results I gathered do not reflect my conclusion because as I have stated in my conclusion I am basing it on scientific theory and not on my results. If had made it from my results then I would have a conclusion that does not make sense and is obviously wrong. My results do not affect my conclusion at all. As shown in my graphs there is no relationship between any of my results so I disregarded them.
Improved Method:
From the internet: The 1425 Semimicro Calorimeter is a compact and easily operated, static jacket, combustion calorimeter designed specifically for measuring the heat of combustion of small samples when only limited amounts of test material are available.
The need for semimicro operation frequently arises in marine biology and other ecological studies where sample sizes are limited, also for testing heat powders and pyrotechnic mixtures. Samples that contain their own oxidizers can be burned in an inert atmosphere while others can be burned in oxygen. However, the 1425 Calorimeter must not be used for self-oxidizing samples if the reaction liberates considerable gas, due to the dangerous pressures that might develop in the bomb.
A bomb calorimeter similar to this could be used to improve the accuracy of my experiment and would provide hopefully better results.
