Heat Energy Investigation

Heat Energy Investigation
Heat Energy Investigation In this experiment we will as accurately as possible measure the voltage, current, time, start temperature, final temperature and the mass of 7 different substances. We will measure the voltage to make the experiment more accurate, we will do this by making sure that every time we do an experiment we will keep the volts to 12v and nothing else, as this could affect the overall result. It is also needed as part of an equation that will be done later on. We will measure the time, start temperature and final temperature because we again need it as part of an equation, which will help us to find out how much energy was needed to make the substance rise by 1o. We need to know the mass of the substance to make it a fair test and as part of the equation. We intend to safely heat up seven different substances; these are steel, oil, water, brass, aluminium, sand and copper. They will be heated to a final temperature of 50oc. We will then do some equation to find out how much energy is needed to make each substance go up by 1o. I predict that the oil and water which are both liquids will take more energy to heat up than the solids.
Because the bonds in the liquids are free flowing and therefore when the substances are heated there is a smaller knock on effect than in the solid substances. By using class results as well as our own we will be able to get a good set of results and will also be able to find out how accurate our own results were. To make the results as accurate as is possible we will not let the metals get too hot and with the liquids we shall stir it so that there is an even temperature throughout. Once we have our measurements: E.g. Steel Voltage = 12v Current = 3.57A Time = 5m 10 sec (310 sec) Start temp = 24o Final temp = 50o Mass = 1Kg We shall do this equation: Energy = voltage X current X time E.g. 10 X 3.57 X 310 = 13,280 final temp ? start temp 50 ? 24 = 510 510 J per Kg per oC 510 J/KgoC According to some preliminary work we carried out, the results should be around: Sand = 800 J/KgoC Brass = 400 J/KgoC Oil = 2000 J/KgoC Water = 4200 J/KgoC Aluminium = 900 J/KgoC Steel = 500 J/KgoC Copper = 400 J/KgoC Measurements Substance Copper Brass Steel Aluminium Sand Water Oil Mass (Kg) 1 1 1 1 1 0.5 0.5 P.d. (V) 12 12 12 12 12 12 12 Current (A) 2.45 4.3 3.57 4.66 4.3 4.3 4.58 Time (s) 60 170 310 440 235 446 240 Start Temp (oC) 24 25 24 25 22 25 25 Final Temp (oC) 50 50 50 50 50 50 50 Energy put in (J) 1,764 8,772 13,280 24,604 12,126 12,384 10,310 Temp rise (oC) 26 25 26 25 28 25 25 Energy per oC 67 350 510 984 433 495 412 Energy per oC per Kg 707 701 510 984 433 1841 824 Class Average 773 707 700 1605 433 1471 824 Preliminary Work 400 400 500 900 800 4200 2000 Accuracy according to class average %* 91 99 72 61 100** 80 100** Accuracy according to preliminary work % 76 75 98 91 54 44 41 Accuracy of class average according to preliminary work % 52 57 71 56 54 35 41 Results Table.
energy per Kg per oC X 100
class average **We were the only group in the class to obtain results for these. This was the class table of results; the anomalies are highlighted in red. Group Brass Copper Steel Aluminium Sand Water Oil 1 845 679 2 701 735 510 984 433 1832 824 3 578 1824 1110 4 1011 2006 After recalculating what the results would be I have found that these anomalies have affected the overall results, I chose the anomalies by selecting data that was unlike the other ones in the same group. The recalculated results without the anomalies are: Steel = 544 J/KgoC Aluminium = 1915 J/KgoC Water = 1110 J/KgoC The overall accuracy of some of the results (class results v preliminary work) has now improved: Before: Steel 71% After: Steel 91% (+20%) Before: Aluminium 56% After: Aluminium 46% (-10%) Before: There was a negative result on the aluminium because overall this was the worst result of all of them, probably because the liquids were not stirred often enough. There were limitations on this as I could only do anomalies for those that had more than two results, as eliminating a result would only leave me with one, which would make the results worse rather than better. I have done some research into the structure of liquids and solids; this helped me with my prediction. I have learnt that solids heat up faster than liquids because they are denser; this is because the particles are in a regular close packed pattern. And when heated the particles vibrate creating more vibrations and they pass on these vibrations to other areas. And that the denser the substance the easier it is to pass on vibrations and heat, because the particles are closer, the knock on effect is greater than in liquids, which are not as dense as solids. It is not as great an effect in liquids because the particles are free flowing and the bonds are not in such a rigid pattern like solids are. Our results show that Sand (433 J per Kg per oC) was the easiest to heat up and that Water (1841 J per Kg per oC) was the hardest. There was a slight pattern in the results and that is that solids and in particular sand were easier to heat up by 1oC than liquids were. This is the order in which the substances came according to how much energy was used to heat up 1 substance by 1o. 1. Sand = 433 J/KgoC = solid 2. Steel = 510 J/KgoC = solid metal 3. Brass = 701 J/KgoC = solid metal 4. Copper = 707 J/KgoC = solid metal 5. Oil = 824 J/KgoC = liquid 6. Aluminium = 984 J/KgoC = solid metal 7. Water = 1841 J/KgoC = liquid The results were quite good, as they were the most accurate in the class, and in general they were very good, I am pleased with the outcomes that we have had. The accuracy of the results was particularly important because it gave us confidence when doing everything else, and also meant that the careful, precision and accuracy of the experiment had paid off. Aluminium was our worst result and was only 61% accurate; although this was our worst result it was still quite accurate considering the difficulty involved in trying to make the experiment accurate. It is difficult to keep it accurate because some of the heat energy that is produced is lost to its surroundings; this is very difficult to overcome. And is not ideal doing it in a classroom situation, but we managed to get it 61% accurate which is a fair achievement. This was a good way to do the experiment, it was the most practical way to do it in a school environment, and would be impractical to use another method. This method if done well, can be quite accurate, as our results clearly show, however if it is done poorly the results are not quite as good. It depends heavily on the level of accuracy and precautions used, as well as knowledge into how to make it as accurate as possible. To improve the accuracy of the experiment you can do four things, they are: 1. Stir liquids 2. Check same amount of volt is used each time (12v) 3. Have each person check each dial, use two stop watches, double check everything else as well 4. Make sure as much of the substance is touching the probe as possible Our results were quite accurate as five out the seven substances were above 80% accurate. Based on the class average we could work out a percentage as how to how accurate we really were. [image] To conclude we were worked well as a group and produced some excellent accurate results, I am pleased with the outcome of the experiment, and enjoyed it thoroughly. We had a good prediction and were right in what we had predicted. The experiment and following investigation was a success.

Heat Energy Investigation 9.4 of 10 on the basis of 4055 Review.