1. Bellringer: 5/14/2018 What do you already know about waves?
Draw a wave in your notebook.
Where can you find waves?
STOTD

2. Things to know… Concept Symbol Units Period T Seconds (s) Frequency f
Hertz (Hz) or 1/s
Wavelength λ
Meters (m)
Wave Speed Vw
Meters/Second (m/s)
Speed of Light c

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

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
The medium vibrates at right angles to the direction of the wave
Wave moves left to right,
Medium goes up and down
Shaking a Rope
Electromagnetic Waves
end

6. Waves
Wavelength
Crest
Amplitude
Trough
end

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

8. Waves
Compression
Rarefaction
Wavelength
Amplitude
end

9. Properties of Waves
end

10. Properties of Waves Amplitude How much the medium is moved
Bigger Amplitude = More Energy
end

11. Properties of Waves Crest The top on a transverse wave Trough
The bottom on a transverse wave
Compression
Where the medium is close together on a longitudinal wave
Rarefaction
Where the medium is further apart on a longitudinal wave

12. Properties of Waves Period (T) Frequency (f)
Time for 1 wave to occur
Measured in seconds (s)
Frequency (f)
Number of waves in 1 s
Measured in Hertz (Hz)
Period and Frequency are inverses of each other
end

13. Properties of Waves Wavelength (λ)
Distance between 2 identical points on a wave
Example: Crest to crest or trough to trough
end

14. BILL NYE THE SCIENCE GUY!!
Look at your worksheet! Read the questions before we watch the video

15. Properties of Waves Wave Speed (vw) Measured in meters/seconds (m/s)
end

16. Properties of Waves
A wave has a frequency of 360 Hz. If its wavelength is 5 m, what wave’s speed?
A wave is moving with a velocity of 5 m/s. If its frequency is 2.5 Hz, what is the wavelength?
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?
end

17. Properties of Waves Wave Speed changes based on the medium,
Fastest in Solids
Slowest in Gases
Because atoms in a solid are closer together
Light is the Exception
The speed of light = 3.0 x 108 m/s
end

18. Sound Waves Sound is a Longitudinal Wave Intensity (Loudness) Pitch
More Amplitude = Louder
Decibels (dB)
Pitch
High Frequency = High Pitch
end

19. Electromagnetic Waves
Electromagnetic (EM) Wave
Transverse waves with an electric field and a magnetic field at 90° to each other
end

20. 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

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

22. 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

23. Electromagnetic Waves
A gamma ray has a wavelength of 7 x m. What is the frequency of this ray?
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?
A beam of visible light has a frequency of 4.5x1014 Hz.
What is the wavelength of this light?
What color is this light?
end

24. Bellringer:
A gamma ray has a wavelength of 5 x m. What is the frequency of this ray?
A wave is moving with a velocity of 10 m/s. If its frequency is 2.5 Hz, what is the wavelength?
STOTD

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

26. Electromagnetic Waves
end

27. 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
Given off by warm objects
end

28. 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

29. Electromagnetic Spectrum
X-Rays
Used in medicine, and for inspection of objects
Too much exposure can kill tissue
Gamma Rays
Have the shortest wavelength (highest frequency)
Highest penetrating power, and highest energy
end

30. Polarized Light – light vibrates along a single plane Moving in one direction
Used in sunglasses
end
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31. Light passes through without interruption A Window Translucent
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 31

32. The color you see is being reflected by the object
Primary Colors:
Red, Blue and Green
The color you see is being reflected by the object
All other colors are being absorbed
Black- All colors are absorbed
White- All colors are reflected
end 32