Sound Travels Through Materials
Recognise that vibrations from sounds travel through a medium (solid, liquid, or gas) to the ear
What a learner can do afterwards
- Explain that sound vibrations need a material (medium) to travel through — they can't travel in a vacuum
- Give examples of sound travelling through different media: air, water, solid objects
- Describe how a string telephone works: voice vibrates the cup, vibrations travel along the string to the other cup
The lesson
You already know that sound is a vibration. But a vibration cannot travel through nothing. It needs a medium, a material like air, water, or a solid, to carry it all the way to your ear.
Knock on a wooden table while a friend rests their ear on the other end. They will hear the knock clearly. The wood is a solid medium, carrying the vibration from your knuckles straight to their ear.
Water carries sound well too. That is why you can still hear a muffled whistle or a friend's shout when your head is underwater in a pool.
Sound cannot travel through a vacuum, a space with no air or any matter at all. That is why outer space stays silent, even next to a roaring rocket engine.
Sound always needs a medium, air, water, or a solid, to travel from its source to your ear.
Watch it
Where it sits
Where this leads
Jobs that lean on this skill. Follow one to see everything it is built on.
8 questions wait behind this lesson, each with its answer explained. Every answer feeds the sky: stars light as they are learned, and dim when it is time to come back.