Year 4 science · Key Stage 2 · Sound

Year 4 sound: vibrations, pitch and volume explained

In Year 4 science, children discover that every sound is made by something vibrating, and that those vibrations travel through a material such as air to reach the ear. They look for patterns linking the pitch of a sound to the instrument or object making it, and the volume to the strength of the vibrations, and they learn that sounds get fainter with distance.

Sound, pitch and volume, explained

A vibration is a rapid back-and-forth movement. When a guitar string is plucked, a drum skin is hit or a voice box in the throat is used, the object vibrates and makes the air around it vibrate too. Children often cannot see the movement, so teachers make it visible: a few grains of rice on a drum skin jump when the drum is tapped, a plucked ruler blurs at its end, and a hand on the throat feels the buzz while humming. When the vibrating stops, the sound stops.

Sound needs something to travel through, called a medium. Vibrations pass from the source through air, and also through liquids and solids, until they reach the ear, where they make the eardrum vibrate and send signals to the brain. This is why sound can be heard underwater and through a wall. It also means there is no sound in a vacuum, such as outer space, where there is nothing to carry the vibrations. As sound spreads out from its source, the vibrations get weaker, which is why a sound is quieter the further away you are. Some materials absorb sound well, such as thick, soft fabrics, and children may test which makes the best ear defenders.

Pitch means how high or low a sound is. Children look for patterns rather than being given a rule. A short, thin or tightly stretched string, or a small drum, makes a higher pitch. A long, thick or loose string, or a large drum, makes a lower pitch. A pitch is higher when the object vibrates faster, though Year 4 pupils are not expected to count vibrations. Many schools use saucepan lids of different sizes, elastic bands of different thicknesses, or bottles with different amounts of water in them. They also explore instruments from around the world.

Volume is how loud or quiet a sound is. It depends on the strength of the vibrations: pluck a string gently and the vibrations are small and the sound quiet; pluck it hard and the vibrations are larger and the sound louder. Pitch and volume are different things and children confuse them often, so a good deal of lesson time is spent making a sound that is loud and low, then quiet and high. Some schools use a sound-level meter, which measures volume in decibels (dB), though the unit is not required.

Words your child will hear

Vibration: A quick back-and-forth movement that makes a sound.
Source: The object that makes a sound, such as a drum, a speaker or a voice.
Medium: The material that vibrations travel through, such as air, water or a wall.
Pitch: How high or low a sound is. A whistle is high and a tuba is low.
Volume: How loud or quiet a sound is.
Insulation: Using materials to stop or reduce sound passing through, such as foam in earmuffs.
Vacuum: A space with no air or other material in it, such as space. Sound cannot travel through it.

What the National Curriculum says

In Year 4, pupils should be taught to:

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

Objectives from the National Curriculum in England, © Crown copyright, used under the Open Government Licence v3.0.

Try it: finding a pattern with a ruler

Does the length of a plastic ruler that sticks out over the edge of a table change the pitch of the sound?

Make a prediction. “I think the shorter the part sticking out, the higher the sound, because short things like a small whistle sound higher.”
Hold a 30 cm plastic ruler firmly on a table with 25 cm sticking out. Press the end down gently, then let go so it twangs. Keep your face well away from the end. Listen to the sound and watch how the ruler moves.
Change one thing only. Move the ruler so that 20 cm, then 15 cm, then 10 cm sticks out. Press the end down by about the same amount each time, so that only the length changes.

Record what you hear in a table, using the words higher or lower than the last one.

Sticking out  Pitch
25 cm         lowest
20 cm         a bit higher
15 cm         higher still
10 cm         highest

Look for the pattern. The shorter the length that is free to move, the faster it vibrates and the higher the pitch. Only the length was changed on purpose, and the ruler was pressed down by about the same amount each time, so the test was fair and the change in pitch can be linked to the length.

Yes. The shorter the part of the ruler that can vibrate, the higher the pitch. Pressing it down further before letting go would make the vibrations bigger and the sound louder, but would not change the pitch.

Common mistakes and how to help

Mixing up pitch and volume

In everyday speech “high” and “loud” are used loosely, and a shrill, high-pitched sound such as a whistle can seem stronger than a low hum, so the two ideas blur together.

What helps: Use a drum or a pan. Hit it softly and hard (volume changes, pitch stays) then compare a small pan with a big one (pitch changes). Ask your child to describe each sound with both words.

Thinking that sound can only travel through air

We usually hear sounds across a room, so air seems to be the only path. Children are often surprised that they can hear through solid walls or under water.

What helps: Press one ear flat on a table while someone scratches or taps it lightly at the far end. Then lift your head and listen to the same tap through the air. Most children are surprised how much clearer it sounds through the wood.

Believing a bigger instrument or a bigger sound means a higher pitch

Children expect big things to be “more” in every way. Most big instruments, such as a cello or a big drum, are actually lower in pitch than small ones.

What helps: Tap a large and a small saucepan lid gently with a spoon, holding each one loosely. Notice which gives the lower note.

Thinking sound stops at a certain distance because it has been “used up”

Sounds fade, so children imagine they run out. In fact the vibrations spread out over a larger and larger area, so each ear receives a weaker signal.

What helps: Put a quiet source, such as a ticking clock, in a room and walk away from it in steps. Ask your child to say at which point it can no longer be heard, and then to predict whether a louder source would carry further.

How to help at home

Make an elastic band guitar. Stretch three elastic bands of different thickness across an empty plastic tub or biscuit tin. Pluck each one and describe the pitch. Then press a finger on one band to shorten it and see what happens.
Feel the vibration. Rest your fingers lightly on your throat while humming a low note and a high one. Touch a speaker playing music at a comfortable volume, and notice the buzz. Talk about what is vibrating.
Find the quietest place. Try a ticking clock or timer wrapped in different materials, such as a towel, bubble wrap or a plastic bag, and listen from the same distance each time. Which material blocks most sound?
Make a string telephone. An adult makes a small hole in the base of two paper cups or yoghurt pots. Thread a few metres of string through, knot each end inside, and pull the string tight. Take turns talking quietly into one cup while the other person listens. Then let the string go slack and try again: the vibrations travel along the tight string, not through the air.

Everything in Year 4 science

Updated 20 October 2026.