1. Electromagnetic Radiation
Light
Electromagnetic Radiation
EM Radiation
EM Spectrum
Types of EM Radiation

2. A. EM Radiation E=mc2 Electromagnetic Radiation
transverse waves produced by the motion of electrically charged particles
does not require a medium
speed in a vacuum = 300,000 km/s
electric and magnetic components are perpendicular
E=mc2

3. A. EM Radiation Photons tiny, particle-like bundles of radiation
absorbed and released by electrons
energy increases with wave frequency

4. B. EM Spectrum
long 
low f
low energy
short 
high f
high energy

5. C. Types of EM Radiation
Radiowaves
lowest energy EM radiation

6. C. Types of EM Radiation Radiowaves FM - frequency modulation
AM - amplitude modulation
Microwaves
penetrate food and vibrate water & fat molecules to produce thermal energy

7. C. Types of EM Radiation Infrared Radiation (IR)
slightly lower energy than visible light
can raise the thermal energy of objects
thermogram - image made by detecting IR radiation

8. C. Types of EM Radiation Visible Light
small part of the spectrum we can see
ROY G. BIV - colors in order of increasing energy R O Y G. B I V
red
orange
yellow
green
blue
indigo
violet

9. C. Types of EM Radiation Ultraviolet Radiation (UV)
slightly higher energy than visible light
Types:
UVA - tanning, wrinkles
UVB - sunburn, cancer
UVC - most harmful, sterilization

10. C. Types of EM Radiation Ultraviolet Radiation (UV)
Ozone layer depletion = UV exposure!

11. C. Types of EM Radiation X rays higher energy than UV
can penetrate soft tissue, but not bones
Used to be used to size shoes before harmful affects were known.

12. Radiation treatment using radioactive cobalt-60.
C. Types of EM Radiation
Gamma rays
highest energy EM radiation
emitted by radioactive atoms
used to kill cancerous cells
Radiation treatment using radioactive cobalt-60.

13. CHECK UNDERSTANDING
1. A light wave is an electromagnetic wave that has both an electric and magnetic component associated with it. Electromagnetic waves are often distinguished from mechanical waves. The distinction is based on the fact that electromagnetic waves ______.
a. can travel through materials and mechanical waves cannot
b. come in a range of frequencies and mechanical waves exist with only certain frequencies
c. can travel through a region void of matter and mechanical waves cannot
d. electromagnetic waves cannot transport energy and mechanical waves can transport energy
e. electromagnetic waves have an infinite speed and mechanical waves have a finite speed

14. All waves have the same speed which depends on the medium
Check Understanding
a. Which region of the electromagnetic spectrum has the highest frequency?
b. Which region of the electromagnetic spectrum has the longest wavelength?
c. Which region of the electromagnetic spectrum will travel with the fastest speed?
GAMMA RAY
RADIO WAVE
All waves have the same speed which depends on the medium

15. Check Understanding
a. Which color of the visible light spectrum has the greatest frequency?
b. Which color of the visible light spectrum has the greatest wavelength?
VIOLET
RED

16. Light
II. Light and Color
Light and Matter
Seeing Colors
Mixing Colors

17. A. Light and Matter Opaque absorbs or reflects all light Transparent
allows light to pass through completely
Translucent
allows some light to pass through

18. B. Seeing Colors White light contains all visible colors - ROY G. BIV
In white light, an object…
reflects the color you see
absorbs all other colors
REFLECTS
ALL COLORS
ABSORBS
ALL COLORS

19. Video: How Cones and Rods Work Stimulates red & green cones
B. Seeing Colors
Video: How Cones and Rods Work
Stimulates red & green cones
The retina contains…
Rods - dim light, black & white
Cones - color
red - absorb red & yellow
green - absorb yellow & green
blue - absorb blue & violet
Stimulates all cones

20. Test for red-green color blindness.
B. Seeing Colors
Test for red-green color blindness.
Color Blindness
one or more sets of cones does not function properly

21. View Java Applet on primary light colors.
C. Mixing Colors
Primary light colors
red, green, blue
additive colors
combine to form white light
EX: computer RGBs
View Java Applet on primary light colors.

22. View Java Applet on filters.
C. Mixing Colors
Filter
transparent material that absorbs all light colors except the filter color
View Java Applet on filters.

23. C. Mixing Colors Pigment
colored material that absorbs and reflects different colors
Primary pigment colors
cyan, magenta, yellow
subtractive colors
combine to form black
EX: color ink cartridges

24. C. Mixing Colors Light Pigment
When mixing pigments, the color of the mixture is the color of light that both pigments reflect.

25. Bill Nye Explains Color