Where Energy Goes

Friction, heat and efficiency

An interactive lesson with 7 steps, about 6 minutes: you predict, drag and solve, with instant feedback on every answer. It runs in your browser and needs JavaScript.

What you’ll learn

• Friction turns kinetic energy into thermal energy. The total energy is still conserved.
• Energy can’t be created or destroyed, only transformed.
• Efficiency = useful output ÷ total input, which is always less than 100%.

Steps

1. Add friction
2. Where did it go?
3. Nothing is lost
4. Sliding box
5. Sled run
6. Efficiency
7. Winch