Waves & How They Move
Develop a model of waves to describe patterns in terms of amplitude and wavelength, and understand that waves can cause objects to move
What a learner can do afterwards
- Describe a wave using the terms amplitude (height) and wavelength (distance between peaks)
- Demonstrate that larger amplitude means more energy (bigger waves move objects more)
- Model wave patterns using a slinky, rope, or water and describe what they observe
The lesson
You already know that sound is made of vibrations that travel through air and other materials. A wave is a way to draw that movement so you can measure it. Every wave has two measurements: amplitude and wavelength.
Amplitude is the height of a wave. Measure it from the middle line of the wave up to the top of a peak. A tall wave has a big amplitude. A flat, low wave has a small amplitude.
Mia ties a rope to a fence and holds the other end. When she flicks her wrist gently, small waves travel down the rope and a leaf tied to it barely moves. When she flicks her wrist hard, big waves travel down the rope and the leaf bounces high in the air. The bigger amplitude carried more energy.
To find a wave's wavelength, measure the distance from one peak to the next peak with a ruler. Try making waves with a slinky, a rope, or in a tub of water, and look for the peaks and the space between them.
Amplitude is how tall a wave is, wavelength is the distance between its peaks, and a bigger amplitude means more energy to move things.
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.