1. Waves & Wave Properties Introduction to Wave Properties
Unit 10
Waves & Wave Properties
Introduction to Wave Properties

2. A wave is … …a motion of disturbance
Waves “propagate in 3-dimensions”.
Waves move through a medium – the particles do not MOVE WITH THE WAVE!

3. A wave moves through the medium
A wave moves through the medium. The medium does not move WITH the wave motion. The particles in the medium vibrate!
(1:26)

4. General Wave Form
crest
Equilibrium Line
trough

5. There are 2 types of waves
Transverse Wave
Longitudinal Wave
Particle vibration is parallel to wave motion
Particle vibration is perpendicular to wave motion

6. Transverse Wave
Particle vibration is perpendicular to wave motion

7. Slow Motion Video of “Transverse Wave”

8. Longitudinal Wave
Particle vibration is
parallel to wave motion

9. Slow Motion Video of “Longitudinal Wave”

10. Label the following examples as transverse or longitudinal waves.

11. Waves move through the medium!
vibrates
The wave only __________________ the particle,
the particle does not __________ with the wave.
move

12. There are 2 Categories of Waves
Mechanical Waves
Electromagnetic Waves
Need a medium to travel through.
Can travel without a medium
For example, through gas, liquid or solids
For example, through a vacuum

13. And an example of a longitudinal wave!
Sounds waves are…
Mechanical waves!
And an example of a longitudinal wave!

14. Electromagnetic Waves
Light waves are
Electromagnetic Waves
And an example of a
transverse wave.

15. Speed of light = frequency x wavelength
Wave Speed Equation
V=f λ
velocity = frequency x wavelength
c =f λ
Speed of light = frequency x wavelength

16. v = 340 m/s c = 300,000,000m/s Sound needs a medium to travel
Speed of Sound in standard air:
Light can travel through a vacuum Speed of Light in a vacuum:
v = 340 m/s
c = 300,000,000m/s

17. Frequency, Wavelength & Speed

18. Which wave has the lower frequency? Which wave has the higher frequency? Which wave has the lower speed?
Lower frequency
Higher frequency
Same Speed!

19. Which wave has the higher frequency
Which wave has the higher frequency? Which wave has the higher wavelength? Which wave has the higher speed?
higher frequency
Same speed!
higher wavelength

20. What is the relationship between speed, frequency and wavelength?
The only way to change the speed of the wave is to _______________________.
A change in the frequency will change _____________.
A change in the wavelength will change ___________.
To change the medium
wavelength
frequency

21. Interference “The Superposition Principal”

22. Show resultant wave and label each as constructive or destructive interference.
Complete
destructive interference
Constructive interference
Destructive interference

23. Which Wave is the Resultant Wave?
This is the resultant wave!

24. Which Wave is the Resultant Wave?

25. Waves can “Reflect”
Reflection occurs for both mechanical and electromagnetic waves. Sound and light waves can both reflect, but do so with various rules which will later be discussed with examples.
Below are two common examples of sound and light reflecting.
Sound waves can reflect causing what we know as an echo.
Light waves can reflect causing what we know as a mirror effect.

26. Standing Waves
A wave pattern that results when two waves of the same frequency, wavelength and amplitude travel in opposite directions and interfere.

27. Standing Waves have ‘nodes’ and ‘antinodes’
A point in a standing wave which has the maximum amplitude.
Node:
A point in a standing wave which has no amplitude.

28. How many nodes and antinodes are in each standing wave?
Create a Standing Wave!
2 nodes, 1 antinode
3 nodes, 2 antinodes
4 nodes, 3 antinodes

29. The Doppler Effect
An apparent change in frequency due to relative motion.
Examples:
Car music/horn as it drives by
Police sirens
Sonic Boom! (Breaking the sound barrier)
Red shift and blue shift with light waves
High frequency
Low frequency
(0-1min)

30. The Doppler Effect Large apparent wavelength Low Frequency wave
Small apparent wavelength High Frequency wave