In this section, you will look at kinetic and potential energy in systems at the molecular level. Just as thermodynamic properties, such as heat and temperature, can be seen on a macroscopic scale, these properties can also be seen at the microscopic level of molecules.

Translational movement of molecules (seen in fluids such as liquids and gasses)	Vibrational movement of molecules (seen here as an object is impacted by another object)

The following video shows a process called "friction welding." Take a few moments to watch this video. As you are watching the video, think about how the following terms connect with what you are seeing: heat, temperature, pressure, kinetic energy, and potential energy.