1. Waves
Vocabulary 3.1

2. Standards
S8P4. Students will explore the wave nature of sound and electromagnetic radiation.
A. Identify the characteristics of electromagnetic and mechanical waves.
F. Diagram the parts of the wave and explain how the parts are affected by changes in amplitude and pitch.

3. Wave
A disturbance that transfers energy from place to place.

4. Mechanical Wave
Mechanical waves are waves that require a medium. This means that they have to have some sort of matter to travel through.
These waves travel when molecules in the medium collide with each other passing on energy.
One example of a mechanical wave is sound. Sound can travel through air, water, or solids, but it can't travel through a vacuum. It needs the medium to help it travel.
Other examples include water waves, seismic waves, and waves traveling through a spring.

5. Transverse Wave
Waves where the disturbance moves perpendicular to the direction of the wave.
You can think of the wave moving left to right, while the disturbance moves up and down.
Example: a water wave where the water moves up and down as the wave passes through the ocean. Another example is a wave of fans in a stadium (the people move up and down while the wave moves around the stadium). 

6. Crest
The crest is the highest point of a transverse wave. The opposite of the crest is the trough. 

7. Trough
The trough is the lowest part of a transverse wave. The opposite of the trough is the crest.

8. Wavelength
The wavelength of a wave is the distance between two corresponding points on back-to-back cycles of a wave.
For example, between two crests of a wave.

9. Amplitude
The measure of the displacement of the wave from its rest position. The higher the amplitude of a wave, the higher its energy. 

10. Period
The period of a wave is the time between wave crests. It is the inverse of the frequency. 

11. Compressional Wave (Longitudinal)
They produce compression  when traveling through a medium.
Example: A Spring

12. Rarefaction
The part of a compressional/longitudinal wave where the particles of the medium are far apart.

13. Compression
The part of a compressional/longitudinal wave where the particles of the medium are close together.

14. Electromagnetic Wave
a wave (as a radio wave or wave of light) that travels at the speed of light and consists of a combined electric and magnetic effect.

15. Summary