1. Waves Wave Applications are Used in a variety of Ways
U.G. Identify & Describe Characteristics of a Wave
Waves
Wave Applications are Used in a variety of Ways
Humans use “refraction” to improve vision
Bats use “echolocation” to catch food

2. WAVES – Waves enable development of new Technology
U.G. Identify & Describe Characteristics of a Wave
WAVES – Waves enable development of new Technology
A Heads Up Display (HUD) uses mirrors and Lenses
Originally used for Plane Pilots so they won’t have to look down. The “combiner” allows a virtual image while still being able to see through that part of the windshield.

3. WAVES – Waves in the Medical Field
U.G. Identify & Describe Characteristics of a Wave
WAVES – Waves in the Medical Field
“Ultrasound and Doppler Effect”
“Fiber Optics”
“Reflection and Doppler Effect”

4. U.G. Identify & Describe Characteristics of a Wave
San Andreas Fault, California
Destructive Waves
Kobe, Japan 1990’s
Death toll was in the thousands

5. U.G. Identify & Describe Characteristics of a Wave
Operate in X(radio f), K & Ka (microwave & higher microwave frequency ranges; some even in IR range)
Waves used for
Speed Enforcement
U.G. Identify & Describe Characteristics of a Wave

6. Maybe light acts like a wave
U.G. Identify & Describe Characteristics of a Wave
Maybe light acts like a wave
Spectrum
White
Light
Prism

7. We’ll check out why this happens
U.G. Identify & Describe Characteristics of a Wave

8. ID the Hierarchy of Waves Classification and Properties Within
U.G.
ID the Hierarchy of Waves Classification and Properties Within

9. U.G. Identify & Describe Characteristics of a Wave
WHAT’S A WAVE???
What is a Wave Pulse?
Wave = form in which energy travels
Only Energy is transferred
Ex. Slinky
Medium = material which a wave travels through
The Medium does NOT travel with the Energy
Wave Pulse = short burst of Energy

10. U.G. Identify & Describe Characteristics of a Wave
What types of Waves exist?
2 General Categories
Mechanical
Electromagnetic
Do the HUMAN Wave around the room. What traveled? ENERGY
Describe these 2 Categories as the Top 2 in a family tree.
Copy Tree Diagram
on Board
U.G. Identify & Describe Characteristics of a Wave

11. MECH EM (Paricles..ex.) (Light)
Medium required
Thru Vaccuum
(ex. Space hammer seen not heard)
Transv
Long.

12. Describe & give examples of Longitudinal & Transverse WAVES
U.G.
Describe & give examples of Longitudinal & Transverse WAVES

13. 2 Types of Traveling Waves
Longitudinal Waves
Medium moves Parallel to the direction energy travels
(sound)
Transverse Waves
SHOW Family Tree structure: see next hidden slide
Medium moves Perpendicular to the direction energy travels

14. U.G. Identify & Describe Characteristics of a Wave
Slinky Demo – Transmitting a wave “Pulse”
1) Pulse Travels (energy) 2) Pulse Refection (2 types) 3) Vary f 4) Standing Waves 5) 2 Wave types

15. U.G. Identify & Describe Characteristics of a Wave
What about water?
Motion is a combo of Transverse & Longitudinal: note the circular shape of the blue dots

16. Describe what occurs to waves when encountering a change of media
U.G.
Describe what occurs to waves when encountering a change of media

17. NOTICE: To Change the SPEED, you must Change the MEDIUM
U.G. Identify & Describe Characteristics of a Wave
What could the speed of a wave depend on?
Test It Below
Wave Speed depends only
on the Medium's Properties
NOTICE: To Change the SPEED, you must
Change the MEDIUM

18. U.G. Identify & Describe Characteristics of a Wave
What happens when a wave
encounters a different medium?
Some NRG REFLECTS & some Transmits
Reflections off a:
fixed end cause an inversion (flipping) of the pulse
free end cause no inversion
(absorbed)
Less dense to more dense medium
More dense to less dense medium
Acts as a fixed end
Acts as a free end
Simulates a free
or fixed end?
U.G. Identify & Describe Characteristics of a Wave

19. U.G. Identify & Describe Characteristics of a Wave
Test It Below

20. U.G. Identify & Describe Characteristics of a Wave
What happens when a wave
encounters a different medium?
Some NRG REFLECTS & some Transmits
Reflections off a:
fixed end cause an inversion (flipping) of the pulse
free end cause no inversion
N3L
No force
U.G. Identify & Describe Characteristics of a Wave

21. U.G. Identify & Describe Characteristics of a Wave
Wave “Phase” and “Phase Difference”
We will say that 1 complete oscillation (cycle) represents 360o
Label the # of degrees

22. U.G. Identify & Describe Characteristics of a Wave
Wave “Phase” and “Phase Difference”
Each wave cycle has 360o
Each point on the wave is a phase of the wave
Points on the wave 360o apart are said to be in “phase” (or 720o,1080o, etc.)
Points on the wave 180o apart are said to be exactly out of “phase” (or 540o,900o, etc.)
Discuss similar points
Here, show via 2 Spring example when two masses are exactly IN & OUT of phase
Quick Ck of Phase Pts

23. U.G. Identify & Describe Characteristics of a Wave
Wave “Phase” and “Phase Difference”
Each wave cycle has 360o
What point is IN PHASE with point B?
What’s the phase difference b/t these two points
Which point is OUT of PHASE with point B?
What’s the phase difference b/t these two points?
What’s the Phase Difference b/t points A & B?
900
Here, show via 2 Spring example when two masses are exactly IN & OUT of phase
Quick Ck of Phase Pts

24. Describe the Parts of a Wave, and the Measurements that can be made
U.G.
Describe the Parts of a Wave, and the Measurements that can be made

25. Why do you see ripples in a pond?

26. Simulation of a Pond ID: Amplitude, Wavelength, Period & Frequency
Longitudinal or
Transverse?
Click
ID: Amplitude, Wavelength, Period & Frequency
U.G. Identify & Describe Characteristics of a Wave

27. U.G. Identify & Describe Characteristics of a Wave
Displacement vs Position Graphs
Copy this graph as it’s sketched on the chalkboard
Crest = top of wave Trough = bottom of wave
Wavelength = distance of one complete wave cycle
Amplitude = energy of a mechanical wave (ex. Loudness for sound)
Measured in
Decibels
D [m]
Corresponding to the ripple tank... +
Wavelength []
crest
crest
amplitude
x [m]
trough
trough
Line of Equilibrium -
U.G. Identify & Describe Characteristics of a Wave

28. U.G. Identify & Describe Characteristics of a Wave
Wavelength (λ): Distance b/t Crests (2 corresponding points) on a wave
Short Wavelength
Long Wavelength
U.G. Identify & Describe Characteristics of a Wave

29. Displacement (Y) vs Position (X) Graphs
Snapshot (at an instant in time)
Pause Side View of Drip Sim.
d [m]
...like taking a picture... +
Wavelength []
crest
crest
Use Meter Stick to measure WL
amplitude
x [m]
trough
trough
Line of Equilibrium -
U.G. Identify & Describe Characteristics of a Wave

30. Video Clip (throughout an ongoing time)
Displacement vs Time Graphs
Video Clip (throughout an ongoing time)
Imagine your in a boat, anchored.
As waves pass by,
what would the motion be like?
d [m] +
...like tracing a path through time...
crest
crest
Period [T] ?
amplitude
Use Stop watch to measure period
t [s]
trough
trough
Line of Equilibrium -
Period: time for 1 complete wave cycle

31. U.G. Identify & Describe Characteristics of a Wave
“How often”
Frequency = the number of wave cycles per second
Imagine your in a raft out in the ocean.
If your raft oscillates up and down (a complete cycle) once every 4 seconds, then how much of the oscillation occurs in 1 second?
What is the period the radio wave from your favorite radio station? (Transmitted in Megahertz)
Ex.
That’s your frequency
1/4
Raft Q: Get T first  Next get f, then have Ss see the relationship
For radio station, once get and discuss Period & Freq, have students tell WL is small and use PSRT to compute it
PSRT
λ ?

32. Determine Amplitude, Wavelength, Period and Frequency for both waves
Position [m] 2 -2
Displacement [m]
Senteo Quick Check: Click
Time [sec]

33. U.G. Identify & Describe Characteristics of a Wave
Wave Fronts
All of the dark regions represent the crests, and so those points are in phase.
Connecting all In Phase points (crests for ex.) forms the Wave Fronts
The distance between the wave Fronts (crests) is the wavelength.
Add to Board

34. U.G. Identify & Describe Characteristics of a Wave
Wave Speed
Consider a train moving at constant speed and each box car has a length 
dist.
U.G. Identify & Describe Characteristics of a Wave

35. U.G. Identify & Describe Characteristics of a Wave
Wave Speed
Question 1 – Given that radio waves travel at 3 x 108 m/s, determine the wavelength of the radio signal coming for your favorite radio station.
Question 2 – A submarine creates one sonar pulse when at sea. Given the speed of sound in seawater is 1522 m/s and the wavelength of the pulse is 3.5 meters, determine the frequency and period of the sound wave.

36. Determine the speed of each wave.
Position [m] 2 -2
Displacement [m]
Time [sec]

37. Wave Characteristics Worksheet
The worksheet is due in 15 minutes
Power Hungry?

38. Which of these can we answer at this time?

39. Quiz