A wave is a disturbance that travels from one place to another. Waves travel through a medium or space.
Types of Waves
In physics, there are two main types of waves: mechanical and electromagnetic.
A mechanical wave is a wave that is an oscillation of matter. Oscillation is moving back and forth between two points. We use the term vibration for this movement. A swing is an example.
These waves need a medium to travel through. Medium is the substance that carries a wave. For example, the air is a medium. The energy in this type of wave spreads in the same direction as the wave. For example, a sound is a mechanical wave. Sound can travel through air, water, or solids, but it can’t travel through a vacuum. Therefore, there is no sound in space.
An electromagnetic wave is a wave that radiates through space. This is why we also call it an electromagnetic radiation (EM or EMR). They don’t need a medium or matter. They can travel through a vacuum or empty space. Light is an electromagnetic wave.
Direction of Waves
The direction of a wave is the direction in which that wave spreads. However, the disturbance of a wave doesn’t need to move in the direction of the wave. A wave can be transverse, longitudinal, or a surface wave by the direction of its disturbance.
This is a wave where the disturbance moves perpendicular to the direction of the wave. If we think of the wave moving left to right, we can imagine that the disturbance moves up and down. Light is a great example of this wave.
This is a wave where the disturbance moves parallel to the direction of the wave. One of the most common examples of these waves is a spring. If you compress a spring and let it go, the wave and the coils move to the same direction. The sound is also a good example.
A surface wave is a wave that travels along the surface of a medium. It has a circular motion. The waves that travel along the surface of the oceans are great examples of surface waves.
On our next articles about sound waves, you will learn about the properties of waves.