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4th grade · Science · Unit 4 of 14

Waves & Codes

Waves, amplitude, wavelength and sending patterns.

What your child practices

Practices how waves have amplitude and wavelength and can make objects move, and how patterns like codes, flashes and digital signals carry information.

Alabama Course of Study content standard: 4.5; 4.6 · amplitude and wavelength, and how waves carry light, sound and digital information

How we explain it

Children can open this short lesson before they practice.

  1. Waves have high points (crests) and low points (troughs).
  2. Amplitude is a wave's height. Bigger waves carry more energy.
  3. Wavelength is the distance from one crest to the next.
  4. Patterns like Morse code or digital code can send information.

Example: Which ocean wave has more energy: one 1 m tall or one 3 m tall? The taller wave has a bigger amplitude. Bigger amplitude means more energy. Answer: the 3 m wave

Waves & Codes in Alabama

In the Alabama Course of Study, this is unit 4 of 14 in 4th grade Science, after Forms of Energy and before Sound.

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

    Waves at the beach can move…

    • the sun
    • sand and pebbles
    • mountains in a day
    • the moon

  2. Question 2

    A barcode is a pattern of…

    • tastes
    • sounds
    • lines
    • smells

  3. Question 3

    Computers store information as patterns of…

    • colors only
    • 1s and 0s
    • rocks
    • smells

  4. Question 4

    A loud sound has a wave with…

    • no energy
    • a big amplitude
    • a tiny amplitude
    • no amplitude

  5. Question 5

    The low point of a wave is the…

    • peak
    • crest
    • trough
    • roof

  6. Question 6

    Why are digital signals good for sending information?

    • They can be copied without losing detail
    • They are always louder
    • They need no power
    • They are made of water

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