* Waves transfer energy, not matter: Imagine dropping a pebble in a pond. The ripples spread out, but the water itself doesn't travel far. The energy from the pebble is what travels, causing the water molecules to oscillate.
* Medium vs. No Medium: Waves can travel through a medium (like water or air) or through a vacuum (like light). In both cases, it's energy that propagates.
* Types of Waves:
* Mechanical waves require a medium to travel. Examples include sound waves, water waves, and seismic waves.
* Electromagnetic waves can travel through a vacuum. Examples include light waves, radio waves, and X-rays.
In summary: While the medium (or particles in a vacuum) oscillate, it's the energy that travels from the source to the receiver as the wave propagates.
