1. Waves & Their Properties

2. Learning Objectives Define wave properties Analyze wave motion
Construct a model of a wave

3. What are the basic properties of waves?
A wave is a traveling disturbance that carries energy from place to place.

4. Practice
When a ship that is two football fields away from a sailboat passes the sailboat, does the water travel along with the wave from the ship to the sailboat?
100 feet

5. All waves begin as a vibration!
When something moves back and forth repeatedly, this is vibration.
Vibrations create waves.

6. There are two basic types of waves.
Transverse (perpendicular vibration)
Longitudinal (parallel vibration)

7. Can you think of a wave that does not require a medium?
The Medium
Question
The medium is the material through which the wave travels.
Most waves travel through something.
Can you think of a wave that does not require a medium?

8. Wavelength: distance or length of one cycle
Wave Properties
Wavelength: distance or length of one cycle
Crest to Crest
Trough to Trough
Compression to Compression

9. Wave Properties
Period: time for one wave cycle to pass a certain point
Frequency: number of wave cycles per second

10. More Wave Properties
Wave speed: total distance one wave cycle travels in some amount of time
Amplitude: displacement from rest, or amount of vibration

11. How do the wavelengths compare?

12. Sound & Light Each wavelength has a different sound.
Each color of light has a different wavelength.
Shorter Wavelength
Higher Frequency
Higher pitch
Violet

13. Notes on a Piano High C note Middle C Low C

14. Practice
Water waves are seen rising 12 inches above the level with crests arriving to your location every ½ second. The distance between crests is 1 yard. What is the wavelength? What is the period? What is the amplitude?

15. Water Waves Water waves look like transverse waves. (Crests & troughs)
Water wave vibrations are actually circular.

16. What happens when waves interfere with each other?
Vibrational amplitudes may add together.
Increase
in Amplitude
Vibrational amplitudes may cancel each other.
Decrease
in Amplitude

17. Standing Waves
A wave and its reflection can add to produce a standing wave. 
A standing wave is a wave pattern that repeats when the original wave and its reflection add together.

18. Nodes & Antinodes
Nodes are places of no vibration. The wave and its reflection cancel each other. (destructive interference)
Antinodes are places of maximum vibration. The wave and its reflection combine and add together. (constructive interference)

19. Practice How many nodes does each standing wave have?
How many antinodes does each standing wave have?
Where are the places of maximum amplitude?