1. Sound

2. 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.

3. 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.

4. 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.

5. 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.

6. 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.

7. 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.

8. Loudness
• Loud sound
• A recorder blown hard makes a loud sound.
• Soft sound
• A recorder blown gently makes a soft sound.