1. S-58
How are electromagnetic waves different from mechanical waves?
List four members of the electromagnetic spectrum. Two examples are light and radio waves.

2. The Electromagnetic Spectrum and Light
Chapter 18
The Electromagnetic Spectrum and Light
SPS9 Students will investigate the properties of waves
Recognize that all waves transfer energy
Relate frequency and wavelength to the energy of different types of electromagnetic waves and mechanical waves.
Compare and contrast the characteristics of electromagnetic and mechanical (sound) waves.
Investigate the phenomena of reflection, refraction, interference, and diffraction.

3. 18.1 Electromagnetic Waves
How are electromagnetic waves different from mechanical waves?
What is the maximum speed of light?
How do electromagnetic waves differ from one another?
What is the dual nature of electromagnetic radiation?
What happens as light travels farther from its source?

4. 18.1 Electromagnetic Waves
How are electromagnetic waves different from mechanical waves?
Electromagnetic Waves – transverse waves that have a changing magnetic field and a changing electric field
Produced when an electric charge vibrates
Do not need a medium
Transfer of energy by electromagnetic waves is called electromagnetic radiation (EMR)

5. 18.1 Electromagnetic Waves
What is the maximum speed of light?
All electromagnetic waves travel at 300,000,000 m/s in a vacuum
Maximum speed in the universe
Goes slower in other media
186,000 mi/s
Porsche 918 Spyder
Plug in Hybrid
98 mpg
198 mi/hr (0.055 mi/s)

6. 18.1 Electromagnetic Waves
How do electromagnetic waves differ from one another?
Electromagnetic waves still follow the wave equation
The speed is always 300,000,000 m/s
For vacuum – really close for air too, so we use the same number
If frequency increases, then wavelength decreases
v=fl

7. 18.1 Electromagnetic Waves
What is the dual nature of electromagnetic radiation?
Electromagnetic waves sometimes behaves like a wave and sometimes like a stream of particles
travels through a vacuum – particle because waves need a medium
Light refracts – wave because particles don’t bend their path as they change mediums
Einstein – photons – wave packets of energy

8. S-60 A. What is the speed of light in a vacuum?
How do electromagnetic waves differ from one another?
A. What is the speed of light in a vacuum?
B. If a light beam has a wavelength of 6.33x1011 m, what is the frequency?

9. 18.2 The Electromagnetic Spectrum
What waves are included in the electromagnetic spectrum?
How is each type of electromagnetic wave used?

10. 18.2 The EM Spectrum
What waves are included in the electromagnetic spectrum?
The electromagnetic spectrum includes many waves – the following are listed in order of increasing frequency, decreasing wavelength, and increasing energy.
Radio TV
Microwaves
Radar
Infrared
Visible Light
Ultraviolet
X-Ray
Gamma

11. 18.2 The EM Spectrum Radio Waves Radio signals TV signals Microwaves
How is each type of electromagnetic wave used?
Radio Waves
Radio signals
TV signals
Microwaves
Cooking, for a short frequency range
Cell phone transmission
Radar (RAdio Detecton And Ranging)
Bounce off the object for distance
Can tell speed using the Doppler Effect

12. 18.2 The EM Spectrum Infrared Rays Visible Light Transfer heat
How is each type of electromagnetic wave used?
Infrared Rays
Transfer heat
Sensed by heat sensors in your skin
Visible Light
The range that human eyes can detect
ROY G BIV (red, orange, yellow, green, blue, indigo, violet)

13. 18.2 The EM Spectrum Ultraviolet X-Ray Sterilizing items
How is each type of electromagnetic wave used?
Ultraviolet
Sterilizing items
Required to form vitamin D
Tanning and skin cancer
X-Ray
Medical and safety
Can also cause cancers

14. 18.2 The EM Spectrum Gamma Rays Cancer treatment
How is each type of electromagnetic wave used?
Gamma Rays
Cancer treatment
Industry to check pipes
We are constantly bombarded by Gamma rays from the sun

15. S-61 List 6 members of the EM spectrum in order of increasing energy.
What waves are included in the electromagnetic spectrum?
List 6 members of the EM spectrum in order of increasing energy.

16. S-62
What waves are included in the electromagnetic spectrum?
List 6 members of the EM spectrum in order of increasing wavelength.

17. 18.3 Behavior of Light
What three types of materials affect the behavior of light?
How does light behave when it enters a new medium?

18. 18.3 Behavior of Light
What three types of materials affect the behavior of light?
How light behaves when it strikes an object depends on the material the object is made of
Transparent – allows most of the light to pass through it
Translucent – allows light to pass through, but scatters the light
Opaque – either reflects or absorbs the light that strikes it

19. 18.3 Behavior of Light
How does light behave when it enters a new medium?
A number of things can happen to light when it strikes a surface
Reflection – the light waves bounce of the surface
Regular reflection – rays bounce off in an orderly patter
Creates an image
Diffused reflection – no pattern
Only color

20. 18.3 Behavior of Light
How does light behave when it enters a new medium?
Refraction – bending of light when it strikes a surface
Cause objects to look broken
Or even a mirage (light bending due to different temperature layers of air)
Polarization – when light only vibrates in one plane
Reduces glare

21. 18.3 Behavior of Light Diffraction – bending of light around barriers
How does light behave when it enters a new medium?
Diffraction – bending of light around barriers
A hole will act like a new source of the wave
Ripple away from edge

22. 18.4 Color What determines the color of an object?
What are the primary colors of light?
What are the primary colors of pigments?

23. 18.4 Color
What determines the color of an object?
Color depends on
What the object is made of (what colors it will absorb or reflect)
The color of light that strikes the object

24. 18.4 Color
What are the primary colors of light?
Primary colors – three specific colors that combine to create all possible colors
Red, Blue, Green (RBG)
These colors combine to form the secondary colors
Yellow, Cyan, Magenta
The primary colors all combine to form White

25. 18.4 Color Pigment – a material that absorbs light Paint
What are the primary colors of pigments?
Pigment – a material that absorbs light
Paint
Primary pigments are Cyan, Magenta, & Yellow
Ink cartridge colors
They mix to form Black

26. S-62
What waves are included in the electromagnetic spectrum?
List the colors of visible light in order from lowest energy to highest energy.
What are the three primary colors?
What color is formed when they all combine?

27. S-63 What are the three primary pigments?
What waves are included in the electromagnetic spectrum?
What are the three primary pigments?
What color is formed when all three primary pigments are mixed together?
How many colors of light are in a laser?

28. S-64
Yahoo!
Test Day
Hoot Hoot!
Jump with Joy!

29. S-65 What is meant by the wave particle duality of light?
What would have to change about Red, Blue, and Green lights to allow for all the colors found on TV?