Energy released = mass of water x 4.2 x average temperature rise
Mass of burnt fuel
Diagram:
Risk Assessment: Alcohols and hydrocarbons are flammable and vaporise quickly and easily. Take case when igniting them. Wear safety goggles and tuck in ties and tie back hair and stay clear away from flame.
Fair Test: In order to keep it a fair test I must keep the water the same amount which is 150cm³. I should also use the same can and use the same thermometer and the same scales in order to measure the mass of the fuel and the temperature of the water. I should also use the same tap to fill the water and the background room temperature should really be the same.
Results: Run 1
Run 2
Run 3
Result Averages:
My results against the Book of Data:
Graph is on next page…
Conclusion: According to the results the outcome is that if a fuel has more carbons in its atomic structure, the more energy it releases during combustion. This information was received from looking at the Book of Data results and not the results from the experiment. This is because the experiment results have no correlation to the book of data’s results and they are not in numerical order like the results in the Book of Data and they are not as high as the Book of Data’s. Therefore the results from the experiment are anomalous results. So these results are not valid for the use of any concluding.
Evaluation: There are many reasons why this experiment created anomalous results. Mostly they were because of lack of equality of the equipment and methods used in this investigation. The problems outlined were:-
- Time limit of experiment was exceeded in some cases due to mild incompetence
- The apparatus used was not the same in testing
- The start temperature of the water differed
- Some results were taken incorrectly
- The cans position was not the same in height
- The accuracy of the measurements were not as good
In order to solve these problems the method of the investigation has to be altered.
This method must insure that we have made the experiment as fair as possible. To make it fair we must perform more runs for each of the fuel so that the average is as accurate as possible. Also the measurements must be accurate, so we must measure the selected units using more than one different device and the averaging the device so that the measurements are also as accurate as possible. For example measuring the fuel using 3 different scales and averaging the combined measurement to get the accurate mass.
To combat the problem of using different equipment in each run is to ensure that the equipment used is clearly labelled and in a place where the investigators can locate it. Also to make sure that the start temperature is accurate w need to perform the investigations at one time in one place where the room temperature will be the same or place the water refrigerated so the all of the water used has the same temperature to start off with. The steel can placement should be at a specific height so that every time we have to refill or pour out water in the can, the investigators can place the can in the same space so that each test has the same amount of heat exposed to it. In the case of the time limit, the investigators should use stopwatches that alarm or alert the users when the set time for the experiment counts down to the alert to make the time used to perform the experiments are equal.
Therefore the new method is to place 3x150cm³of water in a refrigerator 30 minutes before the start of the experiment and make sure that the water has the same temperature. Then collect the chosen fuel and weigh it in three different calibrated scales and then find the average mass before combustion. Do the same for the average mass after combustion and the same with each fuel. Place the steel can 27cm above the surface the experiment is on. Collect one or two boxes of matches that are the same and are lit the same way. Light the fuel and place three digital thermometers in the can filled with water and correctly countdown 3 minutes on two stopwatches. After the end of the trial measure the temperatures from the three thermometers and then average them out and work out the average temperature rise and the energy released. To make sure that the room temperature is the same and to cut down on time consumption try to get as many people to perform the different experiments at the same time.
