Sound

The harder an instrument is struck, the ........................ the volume.

• louder

• quieter

What is sound?

• Waves that travel in vibrations.

• Vibrations that travel in waves.

True or false? Volume is how high or low a sound is.

• True

• False

Answer explanation

How high or low a sound is is called pitch.

Draw a sound wave where the singer has a high-pitched voice.

Answer explanation

A high-pitched sound has a smaller wavelength - the peaks and troughs are closer together.

Does this person have a quiet or loud voice?

• Quiet

• Loud

Answer explanation

They have a quiet voice as the peaks and troughs are short.

What is the arrow with the question mark pointing to?

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Answer explanation

It's the ear drum!

This is the tightly stretched skin inside the ear that vibrates when sound waves reach it.

What is this?

• ossicles

• cochlea

• ear canal

• ear drum

Answer explanation

This is the cochlea. The cochlea sends electrical signals to the brain which interprets them as sound!

What do we measure volume in?

• cm

• dB

• Hz

• ml

Answer explanation

We measure volume in decibels (dB). The higher the decibels, the louder the volume!

We can use a sound meter to measure sound.

Why does sound get quieter as you move away from a sound source?

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Answer explanation

It gets quieter because sound waves have to travel further.

Order the glass bottles containing different amounts of water from 1 to 5, where

1 makes the lowest-pitched sound when you blow over the top of the bottle and

5 makes the highest-pitched sound.

4

• 5, 2, 4, 1, 3

• 3, 1, 4, 2, 1

Answer explanation

The less water in the bottle, the longer the column of air. Longer columns of air vibrate more slowly, producing lower-pitched sounds.

The more water in the bottle, the shorter the column of air. Shorter columns of air vibrate more quickly, producing higher-pitched sounds.