PPT: Sound | Year 5 Science IGCSE (Cambridge) - Class 5 PDF Download

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S o u n d
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S o u n d
What is Sound? 
Sound is a kind of energy that we can hear. It is made when things move or vibrate, like when you clap your hands or a 
bell rings. The vibrations travel through the air and reach our ears, letting us hear the sound.
Here are some simple examples of sound:
Clapping hands 3 When you clap your hands together, it makes a sound.
Bell ringing 3 When you ring a bell, it creates a sound that you can hear.
Dog barking 3 A dog makes a barking sound that you can hear.
Page 3


S o u n d
What is Sound? 
Sound is a kind of energy that we can hear. It is made when things move or vibrate, like when you clap your hands or a 
bell rings. The vibrations travel through the air and reach our ears, letting us hear the sound.
Here are some simple examples of sound:
Clapping hands 3 When you clap your hands together, it makes a sound.
Bell ringing 3 When you ring a bell, it creates a sound that you can hear.
Dog barking 3 A dog makes a barking sound that you can hear.
How are sounds made?
Vibrations cause sounds
Sounds are made when things vibrate. A 
vibration is a very quick movement back and 
forth. You often cannot see vibrations, but you 
can feel them.
We can see these guitar strings vibrate when we pluck 
them. The vibrating strings disturb the air around them, 
creating sound waves that travel to our ears.
Page 4


S o u n d
What is Sound? 
Sound is a kind of energy that we can hear. It is made when things move or vibrate, like when you clap your hands or a 
bell rings. The vibrations travel through the air and reach our ears, letting us hear the sound.
Here are some simple examples of sound:
Clapping hands 3 When you clap your hands together, it makes a sound.
Bell ringing 3 When you ring a bell, it creates a sound that you can hear.
Dog barking 3 A dog makes a barking sound that you can hear.
How are sounds made?
Vibrations cause sounds
Sounds are made when things vibrate. A 
vibration is a very quick movement back and 
forth. You often cannot see vibrations, but you 
can feel them.
We can see these guitar strings vibrate when we pluck 
them. The vibrating strings disturb the air around them, 
creating sound waves that travel to our ears.
How well does sound travel 
through different materials?
Air
Sound travels through air at approximately 343 meters per second, 
allowing us to hear sounds from distant sources.
Water
Sound travels about four times faster through water than through 
air, which is why underwater sounds can be heard from greater 
distances.
Solids
Sound travels fastest through solid materials like metal and wood, 
as their molecules are closer together and can transfer vibrations 
more efficiently.
Page 5


S o u n d
What is Sound? 
Sound is a kind of energy that we can hear. It is made when things move or vibrate, like when you clap your hands or a 
bell rings. The vibrations travel through the air and reach our ears, letting us hear the sound.
Here are some simple examples of sound:
Clapping hands 3 When you clap your hands together, it makes a sound.
Bell ringing 3 When you ring a bell, it creates a sound that you can hear.
Dog barking 3 A dog makes a barking sound that you can hear.
How are sounds made?
Vibrations cause sounds
Sounds are made when things vibrate. A 
vibration is a very quick movement back and 
forth. You often cannot see vibrations, but you 
can feel them.
We can see these guitar strings vibrate when we pluck 
them. The vibrating strings disturb the air around them, 
creating sound waves that travel to our ears.
How well does sound travel 
through different materials?
Air
Sound travels through air at approximately 343 meters per second, 
allowing us to hear sounds from distant sources.
Water
Sound travels about four times faster through water than through 
air, which is why underwater sounds can be heard from greater 
distances.
Solids
Sound travels fastest through solid materials like metal and wood, 
as their molecules are closer together and can transfer vibrations 
more efficiently.
Volume and Pitch
Volume
The volume of a sound is how loud or quiet it is. A sound is louder when the vibrations are bigger.
Decibels
A decibel (dB) is the unit we use to measure sound. Very loud sounds (louder than 85dB) can damage our ears.
Hearing Protection
Exposure to sounds above 85dB for extended periods can cause permanent hearing damage.