Sound

Introduction

• Sounds are vibrations that can travel through different materials.

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

• The loudness of a sound is how loud or soft it is.

Sounds & Vibrations

• Sounds are made when objects vibrate. The vibration makes the air around vibrate, and the air vibrations enter your ear. You hear them as sounds.

• You cannot always see the vibrations, but if something is making a sound, some part of it is always vibrating.

Sound travels through materials

• 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 travels through materials

• Sound vibrations travel better through some materials than others. For example, sound vibrations travel very well along metal pipes.

• 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 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.

Loudness

• The loudness of a sound is how loud or soft the sound is.

• A guitar string plucked strongly makes a loud sound. A guitar string plucked gently makes a soft sound.

• A drum skin hit hard makes a loud sound. A drum skin hit gently makes a soft sound.

Loudness• Loud sound

• A recorder blown hard makes a loud sound.

• Soft sound

• A recorder blown gently makes a soft sound.