We will be measuring the Specific Heat Capacity of aluminium with the calorimeter. The definition of Specific Heat Capacity is the amount of heat energy needed to produce a temperature rise of 1ºK in 1 kg of a substance.
Data Collection
Mass of calorimeter = 1022.15g (0.005g) = 1.02215kg
Total time in seconds = 10 minutes 60 seconds = 600 seconds (approx. 0.005 sec)
V1 = Voltage of 1st trial = 8.4 Volts (0.005V)
I1 = Ampere of 1st trial = 3.0 Amperes (0.005A)
V2 = Voltage of 2ndrial = 9.0 Volts (0.005V)
I2 = Ampere of 2ndrial = 3.2 Amperes (0.005A)
<First Trial>
<First Trial>
<Second Trial>
<Second Trial>
Data Analysis
The following equations are deducted from the original equation for the specific heat capacity.
(Specific Heat Capacity =)
=CM (C is constant for material) Hence, =M (T2-T1)
= VoltageCurrentTime = VIT = M (T2-T1) + H
(Electrical energy supplied to block = Heat Energy gained by block + Heat lost to surroundings)
(1) V1 I1 T = M C (T2-T1) + H
(2) V2 I2 T = M C (T4-T3) + H
(3) = (2) – (1) = (V2 I2 – V1 I1) T = M C [(T4-T3) - (T2-T1)]
V = Voltage / I = Ampere / T = Time / M = Mass / C = Specific Heat Capacity
* H stands for the heat lost to surroundings
(3) = (V2 I2 – V1 I1) T = M C [(T4-T3) - (T2-T1)]
= (9.03.2 –8.43.0) 600 = 1.02215 C [(53-35) - (39-25)]
= (9.03.2 –8.43.0) 600 = 1.02215 C [(53-35) - (39-25)]
C = 528.29 J Kg-1ºK-1
C (Specific Heat Capacity of Aluminium) = 528.29 J Kg-1ºK-1
Evaluation & Conclusion
The value that we get is 528 J Kg-1ºK-1. Theoretically, the Specific Heat Capacity of Aluminium is 897J g−1 ºK−1. I presume that we may have lost some of the heat to the air as well as to metal expansion. In order to minimize the error due to heat, we repeated the same experiment with different levels of power. This allows us to minimize the uncertainties due to heat loss by isolating them from the original equation.
Even though we were tried to lower the value of error, it was difficult to minimize it without completely insulating the calorimeter.
There are some doubts about the fact that the heater is sometimes warming the calorimeter quickly, whilst it sometimes takes a longer period. I am not sure about the reason for this phenomenon. Sensible variations were detected during the experiment. A suggestion would be to use a more accurate heater or digital thermometer for further testing.
In order to get more precise data, we should definitely insulate the calorimeter to minimize its heat lost to the surroundings. For instance, we may place bubble wrap, foil or Styrofoam around the calorimeter.
To obtain more accurate results in the future, a good idea may be to perform the experiment more than twice. Even if the heat loss variable is set aside after more than one experiment, we might get more reliable data by overcoming the variations we have observed in heat transmission between the heater and calorimeter.
