Physics – 3.1 General properties of waves | e-Consult

1. Description of displacement and wave direction:

In a longitudinal wave, the displacement of the particles (in this case, the coils of the slinky) is parallel to the direction in which the wave propagates. This means that as the wave travels, the coils of the slinky move back and forth in the same direction as the wave is moving. The compressions and rarefactions (regions of high and low density) travel along the slinky in the same direction as the pushes and pulls.

2. Explanation for sound and P-waves being longitudinal:

Sound waves and P-waves are longitudinal because they involve compressions and rarefactions of the material through which they travel. The particles of the medium vibrate parallel to the direction the wave is moving. For sound waves, the vibrations are typically in the same direction as the sound is traveling (e.g., from a speaker to your ear). For P-waves, the compressions and rarefactions propagate through the Earth's interior, and the particles of the rock vibrate back and forth in the same direction as the wave's propagation. This characteristic vibration pattern is a defining feature of longitudinal waves.