Patterns & Codes for Information · seed 1 · A4, ink-friendly. The answer key prints on its own page for grown-ups.

Codes and signals: patterns that carry messages

Science · Waves, Light & Sound · ages 9-10
Name ______________________   Date ____________

  1. Sailors held flags in different positions to send messages across water. What is this system called?

    • Morse code
    • Semaphore
    • Braille

  2. Which of these is a code built from patterns of light or sound?

    • Morse code
    • A math worksheet
    • A grocery list

  3. Morse code and semaphore are both systems that use patterns to send information.

    Circle one:   True   False

  4. You want to send a message using only a flashlight at night. Which pair of signals could you build a simple code from?

    • A short flash and a long flash
    • A short flash and a drawing
    • A long flash and a spoken word

  5. In a made-up flashlight code, a short flash means 'yes' and a long flash means 'no'. What does this pattern spell out in order?

    dotdashdot
    • no, yes, no
    • yes, yes, no
    • yes, no, yes

  6. Which system works best when it is too dark to see and too far away to shout?

    • Semaphore flags
    • Drum beats
    • A handwritten note

  7. Priya says Morse code can only be sent using light, never using sound. Is she right?

    Circle one:   True   False

  8. Mateo wants to send a message across a foggy lake where nobody can see far. Which system should he pick, and why?

    • Semaphore flags, because they use light
    • A written letter, because it arrives fastest
    • Drum beats or a horn, because sound still travels through fog
LightMySky · lightmysky.comW1-mt_n5_Jt4ExUd-s1

Answer key

For grown-ups. Fold this page away before handing over the rest.

Codes and signals: patterns that carry messages W1-mt_n5_Jt4ExUd-s1

  1. Semaphore · Semaphore uses flag positions as a pattern that stands for letters, so ships can read it from far away.
  2. Morse code · Morse code uses patterns of dots and dashes, sent as flashes or beeps, to stand for letters.
  3. True · Both turn a message into a pattern: Morse uses dots and dashes, semaphore uses flag positions.
  4. A short flash and a long flash · A code needs signals your friend can actually receive at night, so two flash lengths work well with a flashlight.
  5. yes, no, yes · Read the pattern in order: short flash is yes, long flash is no, short flash is yes again.
  6. Drum beats · Drum beats travel as sound over long distances, so they work even without light or a clear view.
  7. False · Morse code can be flashed as light or beeped as sound. The pattern of dots and dashes stays the same either way.
  8. Drum beats or a horn, because sound still travels through fog · Fog blocks light, so a code built from sound works better than one built from flags.
Worksheet · LightMySky