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8th grade · Science · Unit 3 of 7

Kinetic & Potential Energy

Energy of motion and stored energy.

What your child practices

Practices how kinetic energy depends on mass and speed, how potential energy changes with position, and how energy transfers change an object's motion.

Maine Learning Results learning standard: MS-PS3-1; MS-PS3-2 · kinetic energy, mass and speed, and potential energy and position

How we explain it

Children can open this short lesson before they practice.

  1. Kinetic energy is energy of motion; it grows with mass and speed.
  2. Potential energy is stored by position; higher up means more.
  3. Energy changes form: a falling ball turns potential into kinetic energy.

Example: Where does a roller coaster have the most kinetic energy? Kinetic energy is greatest where it is fastest. It is fastest at the bottom of a hill. Answer: at the bottom of the hill

Kinetic & Potential Energy in Maine

In the Maine Learning Results, this is unit 3 of 7 in 8th grade Science, after Motion, Forces & Newton’s Laws and before Fields & Forces at a Distance.

Gradelings describes a child's practice on this unit as Beginning, Approaching, Meeting or Exceeding (Four practice steps). That reflects practice, not a report-card mark: the teacher decides the mark.

Source: Maine Department of Education

Sample questions

A taste of this unit. In the app, questions change every time and get easier or harder to match your child.

  1. Question 1

    Water held behind a dam has…

    • sound energy only
    • gravitational potential energy
    • no energy
    • kinetic energy only

  2. Question 2

    Which has more kinetic energy?

    • A bike at 50 km/h
    • A ball at rest
    • A truck at 50 km/h
    • A parked truck

  3. Question 3

    A ball thrown upward slows down because kinetic energy changes into…

    • potential energy
    • mass
    • light
    • nothing

  4. Question 4

    Energy can't be created or destroyed, only…

    • multiplied
    • transferred or transformed
    • invented
    • deleted

  5. Question 5

    If speed doubles, kinetic energy…

    • halves
    • doubles
    • stays the same
    • becomes four times as large

  6. Question 6

    Two balls roll at the same speed; one has 3 times the mass. Its KE is…

    • the same
    • one-third
    • 9 times as much
    • 3 times as much

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