Take an eraser and rub it vigorously against any surface. You can show that temperature is related to the kinetic energy of molecules by a simple demonstration. Thermal energy is one of the subcategories of internal energy, as is chemical energy. The total internal energy of a system is the sum of the kinetic and potential energies of its atoms and molecules. Faster moving molecules have greater kinetic energies, and so the substance has greater thermal energy, and thus a higher temperature. Without going into mathematical detail, we can say that thermal energy-the energy associated with heat-is the average kinetic energy of the particles (molecules or atoms) in a substance. Recall that kinetic energy is the energy of motion, and that it increases in proportion to velocity squared. Since heat, like work, transfers energy, it has the SI unit of joule (J).Ītoms and molecules are constantly in motion, bouncing off one another in random directions. This is because we are sensitive to the flow of energy by heat, rather than the temperature. For example, we may say that the heat was unbearable, when we actually mean that the temperature was high. Temperature is literally defined as what we measure on a thermometer. Temperature is defined in terms of the instrument we use to tell us how hot or cold an object is, based on a mechanism and scale invented by people. Heat is the transfer of energy due to a temperature difference. It is tempting to say that temperature measures heat, but this is not strictly true. What is temperature? It’s one of those concepts so ingrained in our everyday lives that, although we know what it means intuitively, it can be hard to define. (G) analyze and explain everyday examples that illustrate the laws of thermodynamics, including the law of conservation of energy and the law of entropy.ĭispel any notions that heat content is solely dependent on temperature.(E) describe how the macroscopic properties of a thermodynamic system such as temperature, specific heat, and pressure are related to the molecular level of matter, including kinetic or potential energy of atoms. ![]() ![]() ![]() The student knows that changes occur within a physical system and applies the laws of conservation of energy and momentum. In addition, the High School Physics Laboratory Manual addresses content in this section in the lab titled: Thermodynamics, as well as the following standards: (E) describe how the macroscopic properties of a thermodynamic system such as temperature, specific heat, and pressure are related to the molecular level of matter, including kinetic or potential energy of atoms.The Learning Objectives in this section will help your students master the following standards:
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