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Sound

  1. A metal bell with the clapper inside that hits it to ring Real photo

    Every sound starts with a shake

    Touch your throat and hum. Do you feel a buzz? Your throat is shaking. Every sound comes from something shaking. These fast little shakes are called vibrations.

    1. 1
      Bell shakes
    2. 2
      Air shakes
    3. 3Ear
      You hear it

    The shake travels to your ear

    A ringing bell shakes the air around it. The shaking air travels to your ears. Then you hear the bell. Sound can travel through water and walls too.

  3. Bell shakesSound travelsEar hears

    Loud and soft

    Tap a bell softly. It shakes a little and sounds soft. Hit it hard. It shakes a lot and sounds loud. Bigger vibrations make louder sounds. Try both taps below.

  4. Thin metal strings stretched across a guitar Real photo

    High and low

    A bird chirp is high. A cow moo is low. Fast vibrations make high sounds. Slow vibrations make low sounds. A short string shakes faster, so it sounds higher.

    1. 1Tap
      wrap shakes
    2. 2Rice
      jumps up

    Try it: see the shake

    Stretch plastic wrap over a bowl. Put a few grains of rice on top. Tap the wrap gently. The rice jumps! You just saw vibrations.

For parents

Goal: Your child learns that sound comes from vibrations, and tells loud from soft and high from low.

  • Ask: what is shaking to make that sound?
  • Make a sound and ask: is it loud or soft? Is it high or low?
  • Have your child gently touch their throat while humming to feel the vibration.

Away from the screen: Stretch rubber bands of different lengths over an open box and pluck them. Listen for which one sounds higher, and watch the bands shake.

Science · Magnets, light and sound
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