1. Categorizing Waves: OR
Based on their ability or inability to transmit energy through a vacuum (i.e., empty space).
electromagnetic waves
mechanical waves. OR
Based on the direction of movement of the individual particles of the medium relative to the direction that the waves travel.
transverse waves
longitudinal waves

2. Electromagnetic waves
An electromagnetic wave is a wave that is capable of transmitting its energy through a vacuum (i.e., empty space).
Electromagnetic waves are produced by the vibration of charged particles.
Electromagnetic waves that are produced on the sun subsequently travel to Earth through the vacuum of outer space.
All light waves are examples of electromagnetic waves.

3. Electromagnetic Spectrum

4. mechanical wave A mechanical wave is a wave that is
not capable of transmitting its energy through a vacuum.
Mechanical waves require a medium (matter) in order to transport their energy from one location to another.
Examples: sound waves, Slinky waves, water waves, stadium waves, and jump rope waves

5. A wave medium is the substance that carries a wave (or disturbance) from one location to another.
a sound wave travels through air
An ocean wave travels through water

6. Direction of energy transport
Longitudinal waves
A longitudinal wave is a wave in which the particles of the medium are displaced in a direction parallel to the direction of energy transport.
Example: sound waves, seismic P (primary or pressure) waves
Direction of energy transport
Source of disturbance

7. Direction of energy transport
A transverse wave is a wave in which the particles of the medium are displaced in a direction perpendicular to the direction of energy transport.
Example: light waves, electromagnetic waves, seismic S (secondary) waves, oceanic (water) waves,
Direction of energy transport
Source of disturbance

9. sources http://www.physicsclassroom.com