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8th grade · Science · Unit 1 of 7

Light & Radiation

Waves, the spectrum and how light behaves

What your child practices

Wavelength and frequency, the electromagnetic spectrum from radio waves to gamma rays and what each is used for, reflection, refraction and color, and staying safe from UV radiation.

Maine Learning Results learning standard: MS-PS4-1; MS-PS4-2 · wave properties and how light reflects, refracts and is absorbed

How we explain it

Children can open this short lesson before they practice.

  1. The electromagnetic spectrum, from longest to shortest wavelength: radio, microwave, infrared, visible light, ultraviolet, X-ray, gamma.
  2. Shorter wavelength means higher frequency and more energy.
  3. Light reflects off mirrors and bends (refracts) when it passes into a new material. Block UV with sunscreen and shade.

Example: Which has a longer wavelength: radio waves or X-rays? Radio waves are at the long end of the spectrum. X-rays are near the short end. Answer: radio waves

Light & Radiation in Maine

In the Maine Learning Results, this is unit 1 of 7 in 8th grade Science, before Motion, Forces & Newton’s Laws.

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

    Light can act as both a wave and a stream of particles. What are the particles called?

    • neutrons
    • protons
    • electrons
    • photons

  2. Question 2

    Longer or shorter wavelength than visible light? Sort each radiation.

    Sort into: 〰️ Longer than visible light · ⚡ Shorter than visible light

    • 📻radio waves
    • 🪫UV from a tanning lamp
    • 🩻X-rays
    • ☢️gamma rays
    • 🌡️infrared
    • 🍿microwaves
    • ☀️ultraviolet
    • 📶Wi-Fi signals

  3. Question 3

    Which type of radiation causes sunburn?

    • infrared
    • microwave
    • radio
    • ultraviolet (UV)

  4. Question 4

    Sound needs matter to travel. Light…

    • can travel through empty space
    • needs air
    • cannot travel through space
    • needs water

  5. Question 5

    Which type of radiation is used to take images of bones?

    • microwaves
    • X-rays
    • infrared
    • radio waves

  6. Question 6

    As the frequency of a wave increases, its wavelength…

    • increases
    • stays the same
    • disappears
    • decreases

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