Physics - Specific Heat Capacity of An Unknown Material Lab Report
Extracts from this document...
Introduction
Lab 15F – Specific Heat Capacity of an Unknown Material Jimmy Cao
Sept. 20/09
What is the specific heat capacity of an unknown material?
Introduction
In this lab, I will be investigating the specific heat capacity of an unknown material. The specific heat capacity of a material is a very important thermal property of a material as it indicates how much energy(heat) in joules is required to raise the temperature of 1kg of this material by 1
C.
Since it is not easy to measure the temperature change of a solid directly, I will be immersing it in water and using the idea of thermal equilibrium to obtain a change in temperature,
. And by adding additional known mass of water at a known temperature and waiting for the mixture to reach thermal equilibrium again, we can use the equation:
Where 
respectively represent the Specific Heat Capacities of the unknown material, water and the
Middle
measurements
...read more.
Temperature of Hot water, | Final temperature, | Mass of hot water, | Temperature of cold water, | Mass of cold water, |
89.5 | 38.5 | 0.057 | 19 | 0.136 |
90 | 39.2 | 0.062 | 18.8 | 0.141 |
79 | 41.9 | 0.094 | 18.1 | 0.135 |
77.8 | 46.5 | 0.140 | 17.8 | 0.141 |
72.5 | 34.1 | 0.065 | 16 | 0.126 |
Raw Data Table for
measurements
Temperature of Hot water, | Final temperature, | Mass of hot water, | Temperature of cold water, | Mass of cold water, |
68.2 | 40.8 | 0.094 | 18.5 | 0.112 |
82 | 47.1 | 0.099 | 20.5 | 0.126 |
81 | 47.6 | 0.094 | 20.1 | 0.110 |
Conclusion
Evaluation
The first design for this lab used an immersion heater and monitoring the power usage with an ammeter and voltmeter. This design involved using the relation,
,
And then graphing 
vs. 
to obtain 
as part of the slope. However, due to the inefficiencies of the immersion heater and the complexity of timing and monitoring temperature and recording data all at the same time, the results ranged from -10
to over 10000. Thus, all the procedures must be changed to using the hot water method currently outlined.
Improvement
Further improvements include using better insulation, to reduce heat loss; this also provides more time to wait for thermal equilibrium to take temperature measurements. Also, by reducing the hot water temperature, the effect of conduction and convection would be reduced. A digital thermometer will greatly improve the errors in temperature measurements as it avoids reading error and great uncertainties. By sanding off the rust flakes that form on the surface, we can also reduce the effect of having impurities in the metal.
This student written piece of work is one of many that can be found in our International Baccalaureate Physics section.
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