1. ELECTROMAGNETIC SPECTRUM

2. Song
The electromagnetic spectrum song

3. Brief review: Water and sound waves transfer energy from one place to another- they require a medium through which to travel. They are mechanical waves. Electric field-region in which charged particles can be pushed or pulled.

4. The theory of electromagnetism explains that electricity and magnetism are closely related.
Electric charges are the source of electric fields.
Moving charges generate magnetic fields.
Waves are the propagation of a disturbance.
They transport energy and momentum but do not transport matter.

5. Video
The electromagnetic spectrum 2 video

6. Nature of Electromagnetic Waves
They are Transverse waves without a medium. (They can travel through empty space)
Transverse means perpendicular to the direction of the wave. (No actual displacement of matter).
They travel as vibrations in electrical and magnetic fields.
Have some magnetic and some electrical properties to them.
Speed of electromagnetic waves = 300,000,000 meters/second (Takes light 8 minutes to move from the sun to earth {150 million miles} at this speed.)

7. When an electric field changes, so does the magnetic field
When an electric field changes, so does the magnetic field. The changing magnetic field causes the electric field to change. When one field vibrates—so does the other.
RESULT-An electromagnetic wave.
Click here Animation: Interaction of vibrating charges

8. Waves or Particles
Electromagnetic radiation has properties of waves but also can be thought of as a stream of particles.
Example: Light
Light as a wave: Light behaves as a transverse wave which we can filter using polarized lenses.
Light as particles (photons)
When directed at a substance light can knock electrons off of a substance (Photoelectric effect)

9. DVD Video
Earthquake DVD
Write down 3 things that you did not know.

10. Earthquake video notes
P waves – primary (first waves)
S waves – secondary (second + waves)
Most damaged caused by S waves
Liquefaction – ground below turns to quick sand due to vibrations and water underground.

11. Video
Eureka Episode 30

12. Eureka Notes
What is white light made of? All the colors combined plus IR (Infrared)
White – reflecting all the colors and IR
Black – absorbs all the colors and IR
What determines what color something is? Which colors it absorbs and which it reflects. (It shows what is reflected)

13. B. Waves of the Electromagnetic Spectrum
Electromagnetic Spectrum—name for the range of electromagnetic waves when placed in order of increasing frequency
Click here (Animation—Size of EMwaves)
GAMMA RAYS
ULTRAVIOLET RAYS
RADIO WAVES
INFRARED RAYS
X-RAYS
MICROWAVES
VISIBLE LIGHT

14. RADIO WAVES
A. Have the longest wavelengths and lowest frequencies of all the electromagnetic waves.
B. A radio picks up radio waves through an antenna and converts it to sound waves.
C. Each radio station in an area broadcasts at a different frequency. # on radio dial tells frequency.
D. MRI (MAGNETIC RESONACE IMAGING)
Uses Short wave radio waves with a magnet to create an image

15. MRI of the Brain

16. Video The electromagnetic spectrum – radio waves
What are three ways that radio waves are used?

17. AM=Amplitude modulation—waves bounce off ionosphere can pick up stations from different cities.
(535kHz-1605kHz= vibrate at 535 to 1605 thousand times/second) +

18. FM=Frequency modulation—waves travel in a straight line & through the ionosphere--lose reception when you travel out of range.
(88MHz-108MHz = vibrate at 88million to 108million times/second) +

19. Bands of Radio/TV/Microwaves

20. AM Spectrum used in Broadcasting and Wirelass
Some common frequency bands
AM radio
535 kilohertz to 1.7 megahertz
Short wave radio
5.9 megahertz to 26.1 megahertz
Citizens band (CB) radio
26.96 megahertz to megahertz
Television stations, channels 2 through 6
54 to 88megahertz
FM radio
88 megahertz to 108 megahertz
Television stations, channels 7 through 13
174 to 220 megahertz
XM Satellite Radio uses microwaves

21. DVD Mapping the Earth’s surface DVD
What part of the electromagnetic spectrum do GPS use?
GPS use radio waves in the microwave part of the electromagnetic spectrum.

22. MICROWAVES
Microwaves—have the shortest wavelengths and the highest frequency of the radio waves.
Used in microwave ovens.
Waves transfer energy to the water in the food causing them to vibrate which in turn transfers energy in the form of heat to the food.
Used by cell phones and pagers.
RADAR (Radio Detection and Ranging)
Used to find the speed of an object by sending out radio waves and measuring the time it takes them to return.

23. Video The electromagnetic spectrum – microwaves
Seeing where the microwaves are… video

24. INFRARED RAYS Infrared= below red
Shorter wavelength and higher frequency than microwaves.
You can feel the longest ones as warmth on your skin
Heat lamps give off infrared waves.
Warm objects give off more heat energy than cool objects.
Thermogram—a picture that shows regions of different temperatures in the body. Temperatures are calculated by the amount of infrared radiation given off. Therefore people give off infrared rays.

26. VISIBLE LIGHT
Shorter wavelength and higher frequency than infrared rays.
Electromagnetic waves we can see.
Longest wavelength= red light
Shortest wavelength= violet (purple) light
When light enters a new medium it bends (refracts). Each wavelength bends a different amount allowing white light to separate into it’s various colors ROYGBIV.

28. Video
The electromagnetic spectrum video

29. ULTRAVIOLET RAYS
Shorter wavelength and higher frequency than visible light
Carry more energy than visible light
Used to kill bacteria. (Sterilization of equipment)
Causes your skin to produce vitamin D (good for teeth and bones)
Used to treat jaundice ( in some new born babies.
Too much can cause skin cancer.
Use sun block to protect against (UV rays)
Sunburn can cause skin cancer

30. X- RAYS Shorter wavelength and higher frequency than UV-rays
Carry a great amount of energy
Can penetrate most matter.
Bones and teeth absorb x-rays. (The light part of an x-ray image indicates a place where the x-ray was absorbed)
Too much exposure can cause cancer
(lead vest at dentist protects organs from unnecessary exposure)
Used by engineers to check for tiny cracks in structures.
The rays pass through the cracks and the cracks appear dark on film.

32. Video
How x-rays work video

33. GAMMA RAYS Shorter wavelength and higher frequency than X-rays
Carry the greatest amount of energy and penetrate the most.
Used in radiation treatment to kill cancer cells.
Can be very harmful if not used correctly.

34. Bone Scan

35. Using the EM waves to view the Sun
Animation—View a Galaxy at different wavelengths

36. B. They all have different wavelength and different frequencies.
Brief SUMMARY
A. All electromagnetic waves travel at the same speed. (300,000,000 meters/second in a vacuum.
B. They all have different wavelength and different frequencies.
Long wavelength-lowest frequency
Short wavelength highest frequency
The higher the frequency the higher the energy.

38. Video
How do your mobile phones work video

39. DVD
Characteristics of waves and ocean - motion of waves DVD

40. Video Plate tectonics video Earthquakes Ring of Fire video
Japan 2011 Earthquake (Youtube)
2004 Boxing Day Tsunami (Youtube)