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
1 · Read
Sound needs a material called a medium to travel through. Air is a gas medium, water is a liquid medium, and wood is a solid medium. A vacuum has no matter to carry sound. Light can cross a vacuum.
Rest your ear gently against a wooden table while a friend taps softly at the other end. Sound can reach your ear through wood or air. Both are possible paths.
Sound can pass through air, a wall, and air again. The solid wall carries vibrations even though you cannot see through it. It reflects or absorbs some sound, so the sound beyond it may be quieter.
A tight string is the solid medium carrying vibrations between telephone cups. Keep the string away from other objects. A slack string usually carries the vibrations less well, so the voice at the receiving cup is weaker.
A tapped helmet can vibrate even when a vacuum surrounds it. If two astronauts have no air or solid path between them and their radios are off, the tap cannot reach the other astronaut as sound. Check the gap, not just whether the source vibrates.
Sound always needs a medium (air, water or a solid) to travel from its source to your ear.
These reading passages were written for this learning dataset. The flashcards describe how materials carry sound.
2 · Watch
Take it off screen
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.