My teacher instructed my class to conduct an experiment to determine the specific heat capacity of Brass, Copper, Aluminium, and Steel. The following setup was used:
The following method was used:
1.) The electric heater (still off) and thermometer are placed into the metal and left for a while.
2.) The start temperature is recorded, the stopwatch is started, and the power pack is turned on.
3.) After aproximately a 10 degree C increase in temperature the timer and power pack are turned off.
4.) As the temperature is still rising, sit and watch the temperature and record the highest temperature it reaches.
6.) Repeat for rest of metals
These were the results
I used the formula http://mypage.bluewin.ch/gutter/formula1.JPG [Broken] to plug in my results (calculating Q by multiplying the time in seconds by 50 (the power of the heater)) and came up with:
748.9 J kg-1 C-1 for Brass
831.2 J kg-1 C-1 for Copper
1615.3 J kg-1 C-1 for Aluminium
747.4 J kg-1 C-1 for Steel
The acutal results were supposed to be (according to my teacher):
370 J kg-1 C-1 for Brass
385 J kg-1 C-1 for Copper
913 J kg-1 C-1 for Aluminium
420 J kg-1 C-1 for Steel
As you can see, my results were about double what they were supposed to be
The Attempt at a Solution
I studied my results much with several people yet I could not find the correct error. My first reaction was to think that much heat had been given off, yet I had used an insulator and even without an insulator, this would not double your results! My second thought was that I had an error in my calculations (sorry I didnt post them, they were a bit long), yet redid the formula three times and everything worked out perfectly. My next suspicion was that my teacher had given me wrong results to confuse me yet a textbook soon disproved that theory. I finally looked at the experiment itself with my father to find an error, but all hope prevailed. I studied several other Methods posted on the internet, yet I noticed no large difference between mine and theirs (they were the same at the base).
In conclusion, I belive the culprit was the heat being given off, even though metal was insulated and placed on a very inconductive surface.
Any and all help would be of great appreciation
(sorry about the lack of equations and such, I am only in high school so I have a limited knowledge of Math and Physics, although I try my best to learn more)
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