Lesson 17: Kinetic and Potential Energy

Kinetic energy is associated with motion, while potential energy is stored through position or arrangement. Rubber bands, ramps, and pendulums show how energy changes within a system and transfers to its surroundings.

Key Ideas

  • Kinetic energy is the energy of motion. Potential energy is stored energy, such as in a stretched rubber band or a raised ball.
  • Energy can change between kinetic and potential energy. A falling ball loses stored energy as it gains motion energy.
  • Energy that comes out of something must come from energy put into it or energy already stored inside it.
  • Energy does not disappear when movement stops. Friction can spread energy into the object and its surroundings as warmth.
  • A material can stay the same while its energy changes. A stretched rubber band is still rubber, but it now stores more energy.

Vocabulary

  • Kinetic Energy: Energy something has because it is moving, like a rolling ball.
  • Potential Energy: Stored energy due to position or shape, like a raised ball or a stretched spring.

Phet Simulation Recommendation: 

https://phet.colorado.edu/en/simulations/energy-skate-park 

Discussion Questions

  1. What is the difference between kinetic and potential energy? Can you give an example of each from your everyday life?
  2. Think about a playground swing. Where does it have the most potential energy? Where does it have the most kinetic energy? What happens in between?
  3. Can you think of something that starts with potential energy and then changes into kinetic energy?
  4. For a coaster released from rest with no later powered boost, why can it not climb above its release height? How would a powered or launched section change the energy account?
  5. If energy can't be created, where does the energy come from when you turn on a flashlight, ride a bike, or jump?
  6. In each demonstration, what energy was already stored and what energy did you supply? Where did it go?
  7. Can something have both potential and kinetic energy at the same time? Think of a roller coaster, bouncing ball, or swinging pendulum.
  8. If you stretch a rubber band and then let it go, where did the energy you put into it go?
  9. What would happen if you could somehow remove all the energy from a moving object? What would happen to its motion?
  10. Energy and matter are different things. Can you think of an example where you add energy to something without adding more matter to it?
  11. What do you think would happen if energy actually could be created? How might that change the world?
  12. Which form of energy do you encounter most often in your daily life: kinetic or potential? Why?

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