Physics Lab Manual
We know that different materials have the ability to store different amounts of heat, given their temperature changes, masses and material. Here we'll investigate and measure the specific heat of different metals.
Recall that if one object releases energy into another by heating, the energy it loses goes into the other object (assuming nothing is lost anywhere else).
Heat Lost from metal = Heat Gained by water
mm cm DTm = mw cw DTw
For water, cw = 4.2 J/g/degree Celsius = 1 calorie per gram per degree Celsius. If we make sure the metal sample is placed in a mass of water equal to TWICE that of the metal sample, then the equation simplifies to:
cm = 2.0 ( DTw / DTm)
This is what we want to find!
Pick three different looking metal samples. Measure their masses.
|mass 1 =|
|mass 2 =|
|mass 3 =|
Bring the water in a metal can to a vigorous boil (so it is at 100 degrees Celsius). Put in the three metal samples and leave them in for at least a minute (so they too get to 100 degrees Celsius).
For mass 1, put TWICE the mass of cool water as the metal sample into the calorimeter (FOAM cups with lid). You can get the mass of water by placing the calorimeter on the scale, zeroing the scale (push "tare"), and then adding water to the desired mass. Alternately, you can measure the volume of the water to get the right mass since, for example, 10 g of water has a volume of 10 ml. Measure the initial temperature of the cool water and record it in the table below.
Using tongs, remove MASS 1 and place it in the calorimeter (quickly shake off drops of hot water first). Measure the highest temperature the water and sample reach. This is the final temperature of the sample. Enter that value in the table too. (DON'T place the thermometer directly on the metal)
Now calculate the specific heat cm for MASS 1 and enter it in the table.
IMPORTANT: Now you must dump out the water in the calorimeter and refill with EXACTLY twice the mass as the second metal sample. Measure its temperature. Repeat the steps above to find the specific heat for MASS 2.
Repeat again for MASS 3. (Don't forget to dump the water again and measure the temperature of the water.)
Enter your experimental values in the table below and use the table underneath to determine which metal you had in your experiment. Also calculate the percentage error between the specific heat that you found and the true value.
|cm(expt)||Type of metal||% error|
|Comment on any sources of error in this lab as you tried to measure the specific heat
of your samples.