Here we focus on those scientific concepts that are the hardest to explain to children. We break it down into what pupils need to know and outline the background science. Even though much of the background science does not need to be taught to primary aged children, it is useful for you as a teacher when addressing misconceptions and children’s challenging questions.

Please refer to your national curriculum documents when planning your sequence of work and ensure that you teach the correct knowledge for your year group.

What do children need to know about sound?

Sounds are ever-present and all around us and therefore learning about sound might appear more straightforward. However, this familiarity is often what leads to misconceptions. Learning about sound is best approached in an exploratory and hands-on way, giving children the opportunity to really experience what happens when sounds are made. We have included some ideas for how to teach sound in part two of this topic guide.

Key scientific concepts: Pupils need to...

1. Know that sounds are made when an object is made to vibrate, and we hear sounds because those vibrations travel to our ears

2. Investigate how sounds can be changed; including pitch and volume

1. Sounds are vibrations

Pupils need to know:

• Sounds are made when an object is made to vibrate

• Vibrations from the object travel through the air to our ears, which is why we hear them

• The vibrations are converted into signals in the brain, so we can recognise the sound

Background science

Sounds are made when objects vibrate. The vibration makes the air molecules around the object vibrate and those air vibrations travel to your ear. Even though you can't always see the object vibrate, if something is making a sound then some part of it is always vibrating. It is important to understand that (unlike light) sound waves need a medium (like air or water) to travel through. 

The trickiest part of this topic is what happens to the vibrations when they enter our ears to enable us to hear the sound. Primary school children do not need to know this, but it is useful for you to understand as a teacher so that you can address misconceptions and answer the questions children will inevitably have.

• Sound waves enter the outer ear and travel through a narrow passageway called the ear canal, which leads to the eardrum 

• The eardrum vibrates from the incoming sound waves and sends these vibrations to three tiny bones in the middle ear 

• These bones amplify the sound vibrations and send them to the cochlea, a snail-shaped structure filled with fluid, in the inner ear 

• This fluid is made to ripple by the vibrations. Hair cells (sensory cells) in the cochlea detect the sounds and stimulate chemicals that create an electrical signal. The auditory nerve carries this electrical signal to the brain, which turns it into a sound that we recognise 

Comparing how animals, including humans, hear sounds is an important connection to make in relation to children’s understanding of the differences between species. Humans, for example, have inferior hearing ability compared to many other animals because our ears are not as large and cannot move independently, which is why we rely more heavily on our sight. Identifying these differences is necessary for understanding how animals can survive in their environment.  

2. Sounds can change pitch and volume

Pupils need to know:

• Changing the pitch of a sound means making it sound higher or lower  

• Changing the volume of a sound (making it louder or quieter) is related to the strength of the vibrations and the distance between the source of the sound and the ear hearing it

• The changes that can be made in the pitch and volume of a sound will depend on the features of the object making the sound

Background science

Pitch (how high or low the sound is) is determined by the frequency of the sound wave. This is not the same as the speed at which it travels, rather it is how close together the peaks and troughs of the wave are; you can think of it as how ‘squashed together’ the sound wave looks. For example, on a guitar a big heavy string will vibrate slowly (with a 'stretched out’ sound wave) and create a low sound or pitch. A thinner lighter string will vibrate faster (with a ‘squashed together’ sound wave) and create a high sound or pitch.

The volume of a sound is determined by the intensity or strength of the sound wave, which is most easily represented by its height. The louder the sound, the higher the peaks of the sound wave will be. To create a louder sound, you need to transfer more energy to the object to create a bigger vibration. For example, if you strike a drum with more force, you transfer more energy to it and cause it to vibrate more, which helps it move more air particles for a longer time.

Ideas to try with your class 

Now you've got the tricky scientific concepts under your belt, try our ideas to help you explore sound with your class in a way they will understand in part two of this topic guide! 

You can also take a look at the related topic guides for animals including humans, light and materials.

Image credit: Human ear with illustrated sound vibrations by New Africa via Shutterstock SL