How can something we can't see be so powerful? Gas molecules make an impact! This video explains their properties: 1. Gas particles always move in a straight line. 2. They are too small to occupy any volume individually. 3. When gas molecules collide, energy is conserved. 4. Individual gas molecules do not attract each other. 5. Gases have energy proportional to their temperatures. After watching the video, the class can review by answering the accompanying questions, or they can investigate further with the provided links to other resources.