The following videos provide a brief explanation of kinetic and potential energy at the atomic level (remember atoms combine to form molecules).

Consider the following questions when viewing the videos:

1. How would you describe kinetic and potential energy in atoms?
2. What is released when energy is transferred?
3. How does this connect to the video about “friction welding”?

Video 1- The Quantum Hypothesis- You only need to watch the first 2 minutes and 5 seconds of this video.

Video 2- Atoms Absorb and Emit Light - You only need to watch the first 3 minutes and 5 seconds of this video.

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Check Your Answers

1. When electrons "get excited" they move to the next energy level and then "fall" back down.
2. Heat and/or light
3. In the friction welding video, atoms in the metal that are being welded are taking in energy. The electrons are "excited" and "jump" to the next level. When they "fall" back down, they release heat and light energy that is seen in the hot, orange glowing part of the weld.

While continuing to think about kinetic and potential energy on a microscopic scale, let’s look at a video about molecular motion. Remember, molecules are groups of atoms bonded together.

Now that you have established a foundation for kinetic and potential energy in atoms and molecules, in the following sections you will explore how the properties of thermal energy, heat, temperature, specific heat, and pressure are involved in these interactions.