Year 4 Science · Sound · Lesson 8.2

Year 4 Science: How vibrations travel to the ear

Part of the Year 4 Science sound chapter. Chapter overview · whole chapter on one page

8.2

How vibrations travel to the ear

Year 4
S2: recognise that vibrations from sounds travel through a medium to the ear

Story. Priya and Leo make a string telephone with two cups and a long piece of string. “I can hear you clearly,” says Leo, when the string is tight. “How does the sound get to my ear?” Mr Patel says, “The vibrations travel along the string.”

Sound needs a medium to travel through. A medium is a solid, a liquid or a gas. The vibrations pass through the medium, one part at a time, until they reach your ear.

When the vibrations reach your ear, they make the eardrum vibrate. You hear the sound because of this.

A string telephone. Vibrations travel along a tight string from one cup to the other cup.

Medium	Example
solid	a wooden table, or a string
liquid	water
gas	air

Key ideas

Vibrations travel through a medium to reach the ear.
A medium can be a solid, a liquid or a gas.
Sound travels through air, water and solids such as a wooden table.
A tight string carries the vibrations along it.

Worked example 8.2.1

Sound travels through a wooden table. What kind of medium is a wooden table? Write the word: solid, liquid or gas.

Method. Read the table in section 8.2.

Find the table row. The solid row includes a wooden table.
wooden table
Name the medium. So a wooden table is a solid medium.
solid
Write the answer.
solid

Check. Wood is a solid. ✓

Worked example 8.2.2

What part of the ear vibrates when the vibrations reach it? Write the word.

Method. Think about the inside of the ear.

Think about the ear. The vibrations make a thin membrane in the ear move.
membrane
Name the part. That thin part is the eardrum.
eardrum
Write the answer.
eardrum

Check. The eardrum is the part that vibrates in the ear. ✓

Worked example 8.2.3

Most sound reaches your ears through a gas around you. Write the name of that gas.

Method. Think about the air around you.

Think about the air. Most sound reaches our ears through the air, which is a gas.
gas
Name the medium. So the medium is the air, which is a gas.
gas
Write the answer.
air

Check. Air is a gas, and it is the usual medium for sound. ✓

Watch out

Watch out: sound needs a medium. It does not travel through empty space, where there is nothing to carry the vibrations.

Try it at home or school (with a grown-up). Make a string telephone with two paper cups and a piece of string, with a grown-up. Keep the string tight. Take turns to speak into one cup, while the other person holds the other cup to their ear. Do not put the cups near anyone’s face.

Exam tip

Grown-up tip. Ask: “What is the sound travelling through? Where do the vibrations go?” Let your child name the medium each time, and say solid, liquid or gas.

Exercise 8B How vibrations travel to the ear

FWhat do vibrations need to travel through to reach the ear? Write the word.

Done

FWhich kind of medium is air: solid, liquid or gas? Write the word.

Done

FWhich kind of medium is water: solid, liquid or gas? Write the word.

Done

FWhich kind of medium is a wooden table: solid, liquid or gas? Write the word.

Done

FWhat is the name of the part of the ear that vibrates when sound reaches it? Write the word.

Done

FCan sound travel through a wooden table? Write yes or no.

Done

FCan sound travel through water? Write yes or no.

Done

FIn the string telephone, what carries the vibrations from one cup to the other? Write the word.

Done

PSMo says sound cannot travel through a table. Is Mo right? Write yes or no.

Done

PSWorking scientifically. Plan a safe test to show that a table carries vibrations. Write one thing you would do.

Done

RExplain why the string telephone needs the string to be tight. Write one sentence.

Done