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8th grade · Science · Unit 16 of 16

Energy Transfers & Waves

Energy is conserved as it changes form, and waves carry energy.

What your child practices

Practices how energy is conserved as it is transferred and transformed in systems such as circuits, food webs, roller coasters and photosynthesis, and how transverse and longitudinal waves carry energy.

Alabama Course of Study content standard: 8.17 · mechanical waves, amplitude and wavelength, and energy transfer

How we explain it

Children can open this short lesson before they practice.

  1. Energy is never made or destroyed; in a closed system the total stays the same.
  2. Energy changes form, and some always becomes heat, often through friction.
  3. Transverse waves shake across the direction they travel; longitudinal waves shake along it, like sound.

Example: Why can’t a roller coaster climb higher than its first hill? Its energy starts as height on the first hill. Friction turns some into heat along the way. Answer: some energy becomes heat from friction

Energy Transfers & Waves in Alabama

In the Alabama Course of Study, this is unit 16 of 16 in 8th grade Science, after Light & Radiation.

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: Alabama State Department of Education (ALSDE)

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

    Sound travels through air as a…

    • light wave
    • transverse wave
    • longitudinal wave
    • ocean wave

  2. Question 2

    Energy is never created or destroyed. It is…

    • lost forever
    • transferred or transformed
    • made from nothing
    • only stored

  3. Question 3

    A coaster never climbs higher than its first hill because some energy is changed into…

    • new mass
    • thermal energy from friction
    • more height
    • light only

  4. Question 4

    Shaking one end of a rope up and down makes a…

    • sound wave
    • longitudinal wave
    • compression wave
    • transverse wave

  5. Question 5

    In a transverse wave, particles move…

    • not at all
    • in circles only
    • in the same direction as the wave
    • at right angles to the wave's direction

  6. Question 6

    Earthquake P waves squeeze and stretch rock along their path. They are…

    • not waves
    • transverse
    • light waves
    • longitudinal

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