Year 4: Sound
Sound
Curriculum Requirement
- Identify how sounds are made, associating some of them with something vibrating
- Recognise that vibrations from sounds travel through a medium to the ear
- Find patterns between the pitch of a sound and features of the object that produced it
- Find patterns between the volume of a sound and the strength of the vibrations that produced it
- Recognise that sounds get fainter as the distance from the sound source increases
Pupils should explore and identify the way sound is made through vibration in a range of different musical instruments from around the world; and find out how the pitch and volume of sounds can be changed in a variety of ways.
Pupils might work scientifically by: finding patterns in the sounds that are made by different objects such as saucepan lids of different sizes or elastic bands of different thicknesses. They might make earmuffs from a variety of different materials to investigate which provides the best insulation against sound. They could make and play their own instruments by using what they have found out about pitch and volume.
National Curriculum in England: primary curriculum, Section: "Sound", p. 163.
What is Sound?
Sound is invisible, but you can feel it. Everything that makes a sound is vibrating. A vibration is just a very, very fast wobble or shake. When something vibrates (like a guitar string), it bumps into the air particles next to it. These particles bump into the particles next to them, and so on, creating an invisible wave of vibrations that travels all the way to your eardrum. Your eardrum vibrates... and your brain says, "I hear a sound!"
Pitch: High vs. Low
Pitch is the word we use to describe how high or low a sound is.
- Fast, small vibrations make high-pitched sounds.
- Slow, big vibrations make low-pitched sounds.
The Robin vs. The Bittern
You can hear this difference in UK birds.
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The Robin:
A robin is small, so its voice box (called a syrinx) is also small. It makes very fast, short vibrations, which create a high-pitched, warbling song.
The Bittern:
A bittern is a large, chunky bird that hides in reed beds. To make its call, it gulps in air and "booms" it out. This creates a very big, slow vibration, resulting in a deep, low-pitched "booom" sound that can be heard from miles away.
💡 Fun Facts
- A bittern's boom is so low-pitched it sounds like someone blowing over the top of a giant milk bottle.
- The tiny Goldcrest, one of the UK's smallest birds, has one of the highest-pitched songs—so high that some older people can't hear it!
- In general, smaller objects vibrate faster and make higher-pitched sounds (like a triangle), while larger objects vibrate slower and make lower-pitched sounds (like a big drum).
Volume: Loud vs. Quiet
Volume is the word we use to describe how loud or quiet a sound is. This depends on the strength or power of the vibration.
- A strong, powerful vibration makes a loud sound.
- A weak, gentle vibration makes a quiet sound.
The Roaring Stag vs. The Rustling Mouse
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The Red Deer Stag:
In autumn, male (stag) red deer try to impress female (hind) deer. They do this by roaring! They use powerful muscles to force a huge amount of air, creating a very strong, powerful vibration. This makes a very loud sound that shows other deer how big and strong they are.
The Wood Mouse:
A tiny wood mouse rustling in the leaves makes very small, weak vibrations. This quiet sound is very hard to hear, which is useful for hiding from predators like owls (who, by the way, have amazing hearing!).
💡 Fun Facts
- A red deer's roar can be as loud as a motorbike (around 100 decibels)!
- Some animals, like bats, make sounds that are too high-pitched for humans to hear. This is called 'ultrasound'.
- The quietest sound a human can hear is 0 decibels. A whisper is about 30 decibels.
How Sound Travels
Sound vibrations need to travel through something to reach you. This 'something' is called a medium.
- Air (a gas) is the medium we usually hear through.
- Sound can also travel through water (a liquid).
- Sound can also travel through walls or the ground (a solid).
Dolphins in UK Waters
Bottlenose dolphins, which you can see in places like the Moray Firth in Scotland or Cardigan Bay in Wales, live in a world of sound.
They 'click' and 'whistle' to each other. These vibrations travel through the water, which is a liquid medium.
💡 Fun Facts
- Sound travels more than four times faster through water than through air. This allows dolphins to communicate over huge distances.
- Dolphins also use sound to 'see' in murky water. They send out high-pitched clicks (echolocation) and listen for the echoes bouncing off fish, which tells them where their dinner is.
- In outer space, there is no air (it's a vacuum). With no medium for the vibrations to travel through, sound can't travel at all. It is completely silent!
Activities & Reflections
Activities
The Ruler Twang
Hold a ruler firmly on the edge of a desk with about half of it sticking off the edge. Twang the end. What do you see? (It's vibrating!) What do you hear? Now, move the ruler so less of it is sticking off (make it shorter) and twang it again. What happens to the pitch? (A shorter ruler vibrates faster, making a higher-pitched sound).
Elastic Band Guitar
Stretch elastic bands of different thicknesses over an empty tissue box or a plastic tub. Pluck the different bands. Which ones make high-pitched sounds (the thin ones)? Which make low-pitched sounds (the thick ones)? How can you make the sound louder? (Pluck the band harder to create a stronger vibration).
String Telephone
Work in pairs. You will need two paper or plastic cups and a long piece of string. Make a small hole in the bottom of each cup. Thread the string through the two cups and tie a knot on the inside of each so it doesn't pull out. One person talks into their cup while the other listens at their cup, making sure the string is pulled tight. The sound vibrations travel along the solid string!
Super Earmuffs
The guidance mentions sound insulation. Challenge pupils to design and make a pair of earmuffs to block out sound. Provide materials like plastic cups, cardboard, cotton wool, fabric scraps, and tape. Which materials are best at stopping the sound vibrations from reaching your ears?
Reflections
Self-Reflection (Exit Ticket)
On a sticky note, answer this: "What is the one-word secret to all sounds?" (The answer is vibrations!)
Paired Reflection (Think-Pair-Share)
Talk to a partner: "If you twang a ruler, how do you make the pitch higher? And how do you make the volume louder?"
Group Reflection
In small groups, discuss: "A loud explosion happens in a space film. Is this realistic? Why or why not?"
Whole Class Share-Out
As a class, discuss: "We learned sound travels through air (gas), water (liquid), and a string (solid). Which one do you think sound travels through the fastest, and why?"
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