Sound+as+a+proverbial+pound

=What is Sound? =

Sounds are vibrations that can travel through different materials. You cannot always see the vibrations, but if something is making a sound, some part of it is always vibrating. When something makes a noise, it sends vibrations, or sound waves, through the air. The human eardrum is a stretched membrane, like the skin of a drum. When the sound waves hit your eardrum, it vibrates and the brain interprets these vibrations as sound. Sounds as vibrations can travel through many different materials.
 * Sound can travel through **solids**, like metal, stone and wood.
 * Sound can travel through **liquids**, like water.
 * Sound can travel through **gases**, like air.

Sound vibrations travel better through some materials than others. Sound cannot travel through a completely empty space (a **vacuum**), which has nothing, not even air, in it. If there is a vacuum between a sound-making object and our ears, we won’t be able to hear the sound.

=Pitch of a sound =

The **pitch** of a sound is how high or low the sound is.

= = A high sound has a high pitch and a low sound has a low pitch.

A **short string** gives a **higher-pitched** sound than a long string when they are plucked.

= = = = = = A **tight drum skin** gives a **higher-pitched** sound than a loose drum skin. = =

= =

=Amplitude of a sound =

The amplitude of a sound is how loud or soft it is.

=<span style="color: #dc4141; font-family: Georgia,serif;"> = <span style="color: #dc4141; font-family: Georgia,serif;">A loud sound has a large amplitude and a quiet sound has small amplitude.

<span style="font-family: Georgia,serif;">A recorder blown hard makes a **loud** sound therefore it has a **large** amplitude.

<span style="font-family: Georgia,serif;">A bass guitar string plucked gently makes a **soft** sound which is a **small** amplitude.