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8th grade · Science · Unit 10 of 11

Digital & Analog Signals

Smooth waves or 0s and 1s: how information travels.

What your child practices

Practices the difference between analog signals (smooth, changing waves) and digital signals (separate values such as 0s and 1s), and the evidence that digital signals encode and send information more reliably, from copying music to radio signals from space probes.

New York State Learning Standards learning standard: MS-PS4-3 · digital signals are a more reliable way to encode and send information than analog signals

How we explain it

Children can open this short lesson before they practice.

  1. Analog signals are smooth waves. Digital signals are separate values, like 0s and 1s.
  2. Eight bits make one byte. Fiber-optic cables carry digital signals as pulses of light.
  3. Digital signals are more reliable because copies don’t pick up noise.

Example: How many bits make one byte? A byte is a group of bits. Answer: 8

Digital & Analog Signals in New York

In the New York State Learning Standards, this is unit 10 of 11 in 8th grade Science, after Space Systems and before Clues from Embryos.

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: New York State Education Department (NYSED)

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

    Cell phones send information using…

    • sound waves
    • radio waves
    • ocean waves
    • earthquake waves

  2. Question 2

    A microphone changes sound waves into…

    • an electrical signal
    • light
    • heat
    • water

  3. Question 3

    A digital song file copied many times…

    • turns into analog
    • keeps the same quality
    • gets worse each time
    • loses all its sound

  4. Question 4

    A bit is…

    • eight letters
    • a single 0 or 1
    • a wave
    • a pixel's color

  5. Question 5

    Fiber-optic cables carry digital signals as…

    • heat
    • pulses of light
    • sound waves
    • water

  6. Question 6

    A weak analog TV picture looks snowy, but a weak digital signal usually…

    • always looks snowy
    • never fails
    • stays clear until it suddenly drops out
    • gets louder

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