Wave Behaviour Vocabulary
Use technical vocabulary for wave behaviour — refraction, absorption, reflection, scattering, amplitude, frequency, wavelength, echo, spectrum, angle of incidence, angle of reflection — and apply these when explaining how light and sound travel and interact with different materials
What a learner can do afterwards
- Use 'refraction' correctly to explain why a straw appears bent in a glass of water
- Distinguish 'reflection' from 'refraction' using the correct definitions
- Explain what an echo is using the vocabulary of sound reflection correctly
The lesson
Light and sound both travel as waves. When a wave hits something, like water, glass, or a wall, it can bounce back, bend, get soaked up, or scatter in all directions. Scientists have exact words for each of these actions.
Reflection means a wave bounces back off a surface. Look in a mirror: light reflects straight back to your eyes. Shout in a canyon and sound reflects back too. That returning sound has its own name: an echo.
Refraction means a wave bends as it moves from one material into another, like from air into water. Light slows down and bends when it enters water, which is why a straw resting in a glass looks like it snaps at the waterline.
Zara puts a pencil in a glass of water and looks from the side. The pencil looks broken at the surface, even though it is perfectly straight. Zara explains: 'The light refracts, it bends, as it moves from air into water. My eyes just follow the bent path, so the pencil looks bent too.'
Don't mix up reflection and refraction. Reflection bounces a wave back. Refraction bends a wave as it passes into a new material. Same first three letters, different job.
Reflection bounces a wave back. Refraction bends it into a new material. An echo is just reflected sound.
Watch it
Where it sits
Learn first
Nothing; this is a starting point.
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.