Waves carry energy from one place to another, but the particles of the medium only oscillate around their original positions and return. Think of a ripple in a pond: the water moves up and down, but the overall water stays in the same spot.
A wave is a disturbance that propagates through a medium (or even through vacuum for light) by transferring energy. The medium’s particles move only locally, never traveling with the wave.
The relationship between wave speed (\$v\$), frequency (\$f\$), and wavelength (\$\lambda\$) is:
\$v = f \lambda\$
Waves do not transport mass. The medium’s particles may move slightly, but they return to their original positions after the wave passes.
| Type | Medium | Typical Speed | Examples |
|---|---|---|---|
| Transverse | String, electromagnetic | ~3.0×10⁸ m/s (light) | Light, radio waves |
| Longitudinal | Air, water, solids | ~340 m/s (sound in air) | Sound, seismic P‑waves |
| Surface | Water surface | Depends on depth & gravity | Ocean waves, ripples |
Remember: In your answers, explicitly state that a wave transfers energy but not matter. Use the phrase “the particles of the medium oscillate but return to their original positions.” This shows you understand the core concept.
Answer Guidance: Describe the oscillation of air molecules, the propagation of pressure changes, and emphasize that the molecules only move a short distance before returning.
Waves are disturbances that carry energy across a medium or through vacuum. The key takeaway is that while energy travels, the medium’s particles do not travel with the wave; they merely oscillate locally.
When answering questions, always mention the phrase “energy transfer without matter transfer” and give at least one concrete example (sound, light, or seismic waves). This demonstrates a clear grasp of the concept.