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Body Lab 3-5 / Week 09 / Monday
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Week 09 · Ears, Hearing and Balance

Monday

Sound is a shake
// Good vibrations and a steady body
⏱ about 15 min

Monday: Sound Is a Shake

Rocket stretches rubber bands around an open shoebox. "My new guitar!" he says. He plucks a band. Twang!

Raven leans close to the box. "What do you notice about the band when it twangs?"

Nova hovers near the box. "Watch the band, not your ears," she says. "Is it still?"

Rocket squints. "It is a blur. It is shaking!"

Shakes make sound

A quick back-and-forth shake is called a vibration.

Vibrating things make sound. A plucked rubber band vibrates, and you hear a twang.

It works the other way too. Sound can make things vibrate.

Your ears use that idea. Sound makes parts inside your ear vibrate.

Then your ears and brain turn those vibrations into the sounds you hear.

SPOT THE VIBRATION
  • Read the question.
  • Tap your answer.
You pluck a rubber band. Why do you hear a sound?
You hum with your fingers on your throat. What do you feel?
A loud drum makes rice on a nearby bowl bounce. Why?
StatementTrue or false?
Vibrating things can make sound.?
Sound can make things vibrate.?
A vibration is a slow, one-way push.?
Parts inside your ear vibrate when sound reaches them.?
WHY THIS EXERCISEA vibration is a quick back-and-forth shake, and it links sound and hearing.
What do we call a quick back-and-forth shake?
WHY THIS EXERCISEA vibration is a quick back-and-forth shake. Vibrations make sound.

Bouncing rice test

  • A bowl
  • Plastic wrap
  • A few grains of dry rice
  • A metal pot and a wooden spoon
Safety first
Rice is for the test only. Nothing goes in your mouth.
Tap the pot gently. Keep the noise at a comfortable level.
Stretch rubber bands gently, and point them away from faces.
  1. Stretch plastic wrap tightly over the top of the bowl.
  2. Sprinkle a few grains of rice on the plastic wrap.
  3. Hold the pot close to the bowl. Tap the pot with the spoon.
  4. Watch the rice. Then tap farther away and compare.
When I tapped the pot, the rice ____.
The sound made the plastic wrap ____.
Try it
Put your fingers gently on the front of your throat.
Hum a long, low note. Then hum a high note.
Notice the buzz. That is your voice vibrating!

Great shaking science! Tomorrow we meet the outer ear, the part that collects sound.