1. Mechanical and Electromagnetic
Waves
Mechanical and Electromagnetic

2. Waves
Wave- a disturbance that carries energy from one location to another location.

3. All waves must have energy to travel.
A wave transports energy and NOT matter!

4. Two types: Transverse waves and Longitudinal waves
Mechanical Waves
Two types: Transverse waves and Longitudinal waves

5. Medium A medium is a substance or material that carries the wave.
The medium is made up of matter, which is a solid, liquid, or gas.

6. Mechanical Waves
Mechanical waves- requires a medium in order to transport their energy.

7. Transverse Waves
A transverse wave- moves in a direction perpendicular to the direction that the wave moves.

8. Examples of Transverse Waves:
Ocean waves
Ripples on water surface
Vibrating guitar strings
Electromagnetic waves

9. Transverse Waves Crest- top of wave Trough- bottom of wave
The line drawn through the center of the diagram represents the rest position.

10. Transverse Waves
Amplitude- is how much energy the wave carries. It is the distance from rest to crest or rest to trough.
Wavelength- can be measured as the distance from crest to crest or from trough to trough.

11. Longitudinal Waves
Longitudinal wave - A wave that has the motion of the medium parallel to the direction of the wave.
Looks like a slinky or spring
Example: sound waves

12. Longitudinal Waves
Rarefaction - where the wave particles are spread apart.
Compression - where the wave particles are close together.

13. Longitudinal vs. Transverse

14. Electromagnetic Waves

15. Electromagnetic Waves
Electromagnetic waves- are waves that are capable of traveling through a vacuum (empty space).
Requires NO medium.

16. Electromagnetic Waves
Examples:
Light waves
Radio waves
Microwaves TV
X-rays
Gamma rays

17. Frequency
Frequency- the number of waves that pass in a given amount of time.
Least frequency are
radio waves.
Higher frequency are gamma rays.

18. Electromagnetic Spectrum

19. Colors of Visible Light
Red
Orange
Yellow
Green
Blue
Indigo
Violet

20. Wave Behaviors
Reflection - The bouncing back of a wave after it hits a surface that it doesn’t go through.
Ex: a mirror

21. Wave Behaviors
Refraction -the slight bending of a wave as the wave passes between two substances.
Ex: Pencil in water

22. Wave Behaviors Diffraction- when a wave is bending around an object.
Ex: sound & light traveling

23. Wave Behaviors
Interference: when two waves combine or meet to form one new wave.
Can be constructive or destructive

24. Wave Behaviors Constructive Interference: creates a larger wave.
Ex: rogue waves in the ocean

25. Wave Behaviors Destructive Interference: creates a smaller wave.
Ex: noise cancelling headphones

26. http://www.solpass.org/6- 8Science/8s/Standards/PS.8activity.htm
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