Answer:
Waves are disturbance of the space (or of a medium) that consist of periodic oscillations that carry energy without carrying matter.
Waves can be of two types:
- Mechanical waves: they are transmitted through the oscillations of the particles in a medium
- Electromagnetic waves: they are oscillations of the electric and magnetic fields. These are the only waves that can travel in a vacuum
Waves consist of periodic vibrations of the particles in a medium that can oscillate in two directions:
- Back and forth along the direction of motion of the wave --> these waves are called longitudinal waves
- Up and down, so perpendicular to the direction of motion of the wave --> these waves are called transverse waves
Waves always propagate from a precise point in space, called source of the wave. So, waves are generated by this source, that somehow does work on the particles of the surrounding medium, and therefore producing the oscillation that then is transmitted through all the space around the source.