Why are sound waves in air characterized as longitudinal?

Explanation

**Step-by-Step Text Solution:**

1. **Understanding Wave Types**: To categorize sound waves, we first need to understand the two main types of waves: longitudinal and transverse waves.

2. **Definition of Longitudinal Waves**: Longitudinal waves are characterized by the movement of particles in the same direction as the wave propagation. This means that when the wave travels, the particles of the medium (in this case, air) vibrate back and forth along the same line as the wave travels.

3. **Sound Wave Generation**: When a sound wave is generated, it starts with a vibration (for example, from a vibrating string or vocal cords). This vibration causes the adjacent air particles to be pushed forward and then pulled back, creating compressions and rarefactions in the air.

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