1. Bike Generator Project
Each lab section will build 1 bike generator
Each lab group will
build 1 energy board
Connect and test energy board and bike generator
Create curriculum materials and demos to teach a class
How current creates a magnetic field
How a motor works
How a generator works
Hypotheses for students to test while riding bike
Handouts that explain activities (electronic versions to me)
VISIT A CLASS and show demos and do activities
Each person will produce a formal lab write-up for this lab project

2. Transverse and Longitudinal Waves

3. Transverse and Longitudinal Waves

4. Wave Speed
The speed of transverse waves on a string stretched with tension Ts is
where μ is the string’s mass-to-length ratio, also called the linear density.

5. EXAMPLE 20.1 The speed of a wave pulse
QUESTION:

6. EXAMPLE 20.1 The speed of a wave pulse

7. One-Dimensional Waves
To understand waves we must deal with   functions of two variables, position and time.
A graph that shows the wave’s displacement as a   function of position at a single instant of time is   called a snapshot graph. For a wave on a string,   a snapshot graph is literally a picture of the wave   at this instant.
A graph that shows the wave’s displacement as a   function of time at a single position in space is   called a history graph. It tells the history of that   particular point in the medium.

8. EXAMPLE 20.2 Finding a history graph from a snapshot graph
QUESTION:

9. EXAMPLE 20.2 Finding a history graph from a snapshot graph

10. Sinusoidal Waves
A wave source that oscillates with simple harmonic   motion (SHM) generates a sinusoidal wave.
The frequency f of the wave is the frequency of the   oscillating source.
The period T is related to the wave frequency f by
The amplitude A of the wave is the maximum value of   the displacement. The crests of the wave have   displacement Dcrest = A and the troughs have displacement   Dtrough = −A.

11. Sinusoidal Waves

12. Sinusoidal Waves
The distance spanned by one cycle of the motion is called    the wavelength λ of the wave. Wavelength is measured in    units of meters.
During a time interval of exactly one period T, each crest    of a sinusoidal wave travels forward a distance of exactly    one wavelength λ.
Because speed is distance divided by time, the wave    speed must be
  or, in terms of frequency

13. Sinusoidal Waves The angular frequency of a wave is
The wave number of a wave is
The general equation for the displacement caused by    a traveling sinusoidal wave is
This wave travels at a speed v = ω/k.

14. Waves in Two and Three Dimensions
Suppose you were to take a photograph of ripples    spreading on a pond. If you mark the location of the    crests on the photo, these would be expanding    concentric circles. The lines that locate the crests are    called wave fronts, and they are spaced precisely    one wavelength apart.
Many waves of interest, such as sound waves or    light waves, move in three dimensions. For    example, loudspeakers and light bulbs emit    spherical waves.
If you observe a spherical wave very, very far from    its source, the wave appears to be a plane wave.

15. Waves in Two and Three Dimensions

16. Waves in Two and Three Dimensions

17. Sound Waves

18. Sound Waves
For air at room temperature (20°C), the speed of sound   is vsound = 343 m/s.
Your ears are able to detect sinusoidal sound waves   with frequencies between about 20 Hz and about   20,000 Hz, or 20 kHz.
Low frequencies are perceived as “low pitch” bass   notes, while high frequencies are heard as “high pitch”   treble notes.
Sound waves exist at frequencies well above 20 kHz,   even though humans can’t hear them. These are called   ultrasonic frequencies.
Oscillators vibrating at frequencies of many MHz   generate the ultrasonic waves used in ultrasound   medical imaging.

19. Test your hearing

20. EXAMPLE 20.6 Sound wavelengths
QUESTION:

21. EXAMPLE 20.6 Sound wavelengths

22. Electromagnetic Waves
A light wave is an electromagnetic wave, an oscillation   of the electromagnetic field.
Other electromagnetic waves, such as radio waves,   microwaves, and ultraviolet light, have the same physical characteristics as light waves even though we cannot sense them with our eyes.
All electromagnetic waves travel through vacuum with   the same speed, called the speed of light. The value of   the speed of light is c = 299,792,458 m/s.
At this speed, light could circle the earth 7.5 times in a   mere second—if there were a way to make it go in   circles!

24. The Index of Refraction
Light waves travel with speed c in a vacuum, but they    slow down as they pass through transparent materials    such as water or glass or even, to a very slight extent,    air.
The speed of light in a material is characterized by the    material’s index of refraction n, defined as

26. Power and Intensity

27. EXAMPLE 20.9 The intensity of a laser beam
QUESTION:

28. EXAMPLE 20.9 The intensity of a laser beam

29. EXAMPLE 20.9 The intensity of a laser beam

30. Intensity and Decibels
Human hearing spans an extremely wide range of    intensities, from the threshold of hearing at ≈ 1 × 10−12    W/m2 (at midrange frequencies) to the threshold of pain    at ≈ 10 W/m2.
If we want to make a scale of loudness, it’s convenient    and logical to place the zero of our scale at the threshold    of hearing.
To do so, we define the sound intensity level, expressed    in decibels (dB), as
where I0 = 1 × 10−12 W/m2.

31. Intensity and Decibels

32. The Doppler Effect
An interesting effect occurs when you are in   motion relative to a wave source. It is called the   Doppler effect.
You’ve likely noticed that the pitch of an   ambulance’s siren drops as it goes past you. A   higher pitch suddenly becomes a lower pitch.
As a wave source approaches you, you will observe   a frequency f+ which is slightly higher than f0, the   natural frequency of the source.
As a wave source recedes away from you, you will   observe a frequency f− which is slightly lower than   f0, the natural frequency of the source.

33. The Doppler Effect
The frequencies heard by a stationary observer when the sound source is moving at speed v0 are
The frequencies heard by an observer moving at speed v0 relative to a stationary sound source emitting frequency f0 are

34. EXAMPLE 20.11 How fast are the police traveling?
QUESTION:

35. EXAMPLE 20.11 How fast are the police traveling?