Understanding of Thermodynamics

Understanding Thermodynamics Through the Concepts of Absolute Zero and the Distribution of Molecular Speeds

Thermodynamics is the study of work, heat, and the energy of a system (NASA, 2010). To help explain in more detail the properties of thermodynamics are the laws of thermodynamics. The first law explains that a system’s internal energy can be increased by adding energy to the system or by doing work on the system (Serway & Vuille, 2012). An internal energy system is the sum of both its kinetic and potential energies. The first law more simply states that the change in internal energy of a system is caused by an exchange of energy across the system, typically in the form of heat, or by doing work on the system. This relationship can be represented by the equation:

ΔU = Q + W

ΔU is the change in internal energy, Q is the energy exchanged (heat), and W is the work done on the system.

Often, energy is exchanged with a gas while work is either done on the gas or by the gas. When work is done on the gas, work is negative; whereas, when work is done by the gas, work is positive (Serway & Vuille, 2012). The internal energy of an ideal gas is represented by the expression:

U = (3/2)nRT

For a monatomic gas where its particles consist of only single atoms, its change in internal energy is represented by the equation:

ΔU = (3/2)nRΔT

n is the number of moles, R is the gas constant (8.31 J/Kmol), and ΔT is the change in temperature measured in Kelvins.

Temperature is measured using many different units throughout the world. Americans in the U.S. typically measure temperature in degrees Fahrenheit. More commonly used throughout the world is degrees in Celsius. In physics, Celsius is also commonly used, along w...

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...ics is also incorporated into the technology of our world, including how energy is taken from a refrigerator and delivered as heat to the kitchen; how a heat engine takes in energy by form of heat and uses that energy to create new mechanical and electrical energy; or how an air conditioner uses a heat pump to extract energy from the cold outside air and delivers energy in the form of heat to the warmer inside air. By understanding how thermodynamics is a study of physics, it will make it easier to recognize its influence on our everyday lives as well.

References

1. Department of Physics. (2010). Physics 174/184 lab manual. Oxford: Kendall Hunt.

2. NASA. (2010). What is thermodynamics?. Retrieved from http://www.grc.nasa.gov/WWW/k-12/airplane/thermo.html

3. Serway, R. A., & Vuille, C. (2012). College physics. (9th ed.). Boston: Cengage Learning.