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?

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?

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.