1. Warm-Up
ACT Question of the Day

2. Waves, Sound, and the Electromagnetic Spectrum
Chapter 17 and 18

3. Things to Know… Concept Symbol Units Period Frequency Wavelength
Wave Speed
Speed of Light

4. Waves Mechanical Wave A disturbance in matter that carries energy
Created by a vibration
Must travel through a medium
Air, water, land, metal, …
Cannot travel through a vacuum (like space!)
2 types: Transverse and Longitudinal
end

5. Waves Transverse Waves
Medium vibrates at 90° to the direction of the wave
Wave moves left to right,
Medium goes up and down
Shaking a Rope
EM Waves (Light)
end

6. Parts of a Wave
end

7. Waves
Wavelength
Crest
Amplitude
Trough
end

8. Waves Longitudinal (Compression) Waves
Medium vibrates parallel to the direction of the wave
Wave moves left to right
Medium moves left to right
A Spring
Sound
end

9. Waves
end

10. Waves
Compression
Rarefaction
Wavelength
end

11. Properties of Waves
end

12. Properties of Waves Amplitude Distance the medium is moved
Bigger Amplitude = More Energy
end

13. Properties of Waves Crest Trough Rarefaction Compression
Height/Top on a transverse wave
Trough
Lowest point on a transverse wave
Rarefaction
Where the medium is far apart on a longitudinal wave
Compression
Where the medium is close on a longitudinal wave
Properties of Waves

14. Properties of Waves Period (T) Frequency (f)
Time for 1 wave
Frequency (f)
Number of waves in 1 s
Period and Frequency are inverses
end

15. Properties of Waves Wavelength (λ) Distance between 2 identical points
end

16. Properties of Waves
Wave Speed (vw)
end

17. Properties of Waves
A wave has a frequency of 360 Hz. If its wavelength is 5 m, what wave’s speed?
end

18. Practice
A wave is moving with a velocity of 5 m/s. If its frequency is 2.5 Hz, what is the wavelength?

19. Practice
The speed of light is 3.0 x 108 m/s. Blue light has a wavelength of 4.5 x 10-7 m, what is its frequency?

20. Properties of Waves Wave Speed changes based on the medium,
Fastest in Solids
Slowest in Gases
Because atoms in a solid are closer together
end

21. Sound Waves Sound Intensity (Loudness) Pitch More Amplitude = Louder
Decibels (dB)
Pitch
High Frequency = High Pitch
end

22. To complete for Chapter 17
Complete wave worksheet and math review problems in your notes…TURN IN WHEN COMPLETE!!!

23. Bell Ringer: 12/2/14 HAVE YOUR REFERENCE TABLES OUT & CALCULATOR!
What is the speed of light?
If the wavelength is short, the frequency is low. True/False
If the wave frequency is high, the wave energy is high. True/False
What is the formula for Wave Speed?
What are the units for frequency? Wavelength? Wave Speed?
Calculate the following problem: If a wave is moving with a velocity of 12m/s, and a wavelength that measures 6m from crest to crest, what is the frequency?

24. Electromagnetic Spectrum

25. Electromagnetic Waves
Electromagnetic (EM) Wave
Transverse waves
Electric and Magnetic Fields at 90°
end

26. Electromagnetic Waves
Created by moving electric charges
Does Not need a medium to travel
Can travel through empty space
EM Radiation
Transfer of energy by EM waves
end

27. Electromagnetic Waves
All EM waves travel at the same speed, as the Speed of Light (c)
c = 3.0 x 108 m/s
Since the speed is the same,
EM waves have different frequencies and wavelengths
As frequency goes up, wavelength goes down
High Frequency = High Energy
end

28. Electromagnetic Waves
If the speed of a wave is:
Then the speed of an EM wave is:
Speed of Light
(3.0x108 m/s)
end
end

29. Electromagnetic Waves
A gamma ray has a wavelength of 7 x m. What is the frequency of this ray?
end

30. Practice A beam of visible light has a frequency of 4.5x1014 Hz.
What is the wavelength of this light?
What color is this light?

31. Practice
A satellite transmits on the EM Spectrum at a frequency of 9.4 x 109 Hz. What is the signal’s wavelength?
What type of wave is being transmitted?

32. Worksheet
Speed of Light Practice Problems (1-5)

33. Electromagnetic Waves
end

34. Electromagnetic Spectrum
EM waves are divided based on their wavelength
Energy
Low
High
end

35. Electromagnetic Spectrum
Radio Waves
Longest wavelengths
Radio and TV
Microwaves
Cooking food and Radar
Only penetrates a few centimeters
Infrared (IR) Rays
Felt as heat
end

36. Electromagnetic Spectrum
Visible Light
What we can see
To remember the colors in order use:
ROY-G-BIV
Red, orange, yellow, green, blue, indigo, violet
Ultraviolet (UV) Rays
Helps your body produce Vitamin D to absorb calcium
Used to kill bacteria
end

37. Electromagnetic Spectrum
X-Rays
Medicine and inspections
Too much exposure can kill tissue
Gamma Rays -STARS
Have the shortest wavelength (highest frequency)
Highest penetrating power, and highest energy
end

38. Polarized Light – light vibrates in one direction Used in sunglasses
Takes out glare
end
end 38

39. Passage of Light Transparent Light passes through without interruption
A Window
Translucent
Light passes through, but is scattered
Wax-Paper or Frosted Glass
Opaque
Light cannot pass through
A Wall.
end 39

40. The color seen, is reflected Other colors are absorbed
Primary Colors:
Red, Blue and Green
The color seen, is reflected
Other colors are absorbed
Black- All colors are absorbed
White- All colors are reflected
end 40