[Leejohnston]

## Waves — Why Everything Oscillates

### 1. The Equation

Wave speed = frequency × wavelength

v = fλ

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### 2. What Each Symbol Means

- v = wave speed
- f = frequency (how often it oscillates)
- λ = wavelength (distance between peaks)

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### 3. What the Equation Is Telling Us

Waves move by repeating patterns.

If frequency increases, wavelength must decrease to keep the same speed.

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### 4. Where It Comes From (Intuition)

A wave is just **repeating motion moving through space**.

More oscillations per second means each oscillation must be closer together.

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### 5. Worked Example

If:
- frequency = 2 Hz
- wavelength = 5 m

v = 2 × 5
= **10 m/s**

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### 6. Real-World Applications

- Sound waves
- Light and radio signals
- Ocean waves
- Earthquakes

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### 7. Common Misconceptions

- Waves move matter forward → false
- Bigger waves move faster → false
- Frequency always changes speed → false

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### Try It Yourself

If frequency doubles, what happens to wavelength?