Sine Waves

Circles become waves

An interactive lesson with 7 steps, about 6 minutes: you predict, drag and solve, with instant feedback on every answer. It runs in your browser and needs JavaScript.

What you’ll learn

• $y = \sin x$ is the height of a point going around the unit circle, with period $2\pi$.
• $y = A\sin(Bx)$ has amplitude $A$ and period $2\pi/B$.
• Frequency is 1 ÷ period, measured in hertz. Anything that repeats can be described by sine waves.

Steps

1. Unroll the circle
2. When does it repeat?
3. Stretching waves
4. Match the wave
5. Period
6. Waves everywhere
7. Ferris wheel