Two Main Wave Types

Overview

Waves are disturbances that transfer energy from one point to another in various forms.
There are two main types of waves: Mechanical waves and Electromagnetic waves.

Mechanical waves require a medium (solid, liquid, or gas) through which to travel.
These waves are created when a source of energy causes a vibration to travel through the medium.
Two types of mechanical waves exist: Longitudinal waves and Transverse waves.

In longitudinal waves, particles in the medium oscillate back and forth along the direction of wave propagation.
Sound waves are a common example of longitudinal waves.
In these waves, areas where particles are close together are known as compressions, while areas where particles are spread out are known as rarefactions.

In transverse waves, particles in the medium move perpendicular to the direction of the wave.
Waves on a string or water surface waves are examples of transverse waves.
These waves have peaks (crests) and troughs (valleys), which represent maximum displacement of the medium.

Unlike mechanical waves, electromagnetic waves do not need any medium to propagate.
They can travel through the vacuum of space since they are generated by the vibration of electric charges.
Examples include light waves, microwaves, radio waves, X-rays and gamma rays.
Similar to transverse mechanical waves, electromagnetic waves have peaks and troughs.

All waves have some common properties:
- Wavelength: Distance between two consecutive corresponding points of a wave, such as from crest to crest or from trough to trough.
- Frequency: Number of wavelengths that pass a certain point each second.
- Amplitude: The maximum extent of a wave from its rest position.
- Speed: The distance a wave travels per unit of time.
These properties help in distinguishing one type of wave from another and understanding the energy transmitted by the wave.

Understanding waves is fundamental to many areas of science and technology such as:
- Communications: Radio and television broadcasts, mobile phone signals, WiFi connections all rely on electromagnetic waves.
- Medicine: Ultrasound (mechanical waves) is used for imaging internal body structures. X-rays (electromagnetic waves) are used to examine fractures, infections and tumors.
- Astronomy: Observations of electromagnetic waves from space can provide information about the universe.