1. Electromagnetic Waves
Ch 18.1

2. Electromagnetic waves travel as fast as the speed of light
True
False
Statement
Electromagnetic waves are longitudinal waves consisting of electric and magnetic fields
Electromagnetic waves can travel though all mediums and through a vacuum/empty space
Electromagnetic waves travel as fast as the speed of light
Electromagnetic radiation can behave like waves and like particles
Intensity of light increases as the photons travel farther from the source

3. Electromagnetic Waves
Transverse waves consisting of changing electric and magnetic fields

4. Electromagnetic Waves
Produced by:
Travel by:
An electric charge vibrating or accelerating
Electric field- produced by charged particles & magnetic fields
Magnetic field- produced by magnets, by changing electric fields & vibrating charges
Vacuum or empty space, as well as matter
Magnetic fields and electric fields regenerate each other
traveling in the form of a wave
Electromagnetic Radiation
Transfer of electromagnetic waves through matter

5. Speed of Electromagnetic Waves
Speed of Light
Michelson’s Experiment
Used mirrors to calculate the speed of light
Light is faster than sound
Lighting 1st
Thunder 2nd
3.00 x 108 m/s
When in a vacuum
Same for electromagnetic waves

6. Wavelength & Frequency
In a vacuum
all electromagnetic waves travel at the same speed
Outside
Different wavelengths and frequencies
SI Units V=
f = Hz
λ= m

7. Math Practice 1. 3. 2.

8. Wave or Particle? Electromagnetic radiation behaves sometimes
like waves and
like a stream of particles

9. Waves and Particles Wave Model Particle Model
Bright Bands indicate constructive interference
Dark Bands indicate destructive interference
Photon- packets of electromagnetic energy
Blue light – high frequency photon
Emission of electrons
Red light- lower frequency photon
No emission of electrons

10. Intensity Rate at which a waves energy flows through a given area
Decreases as photons travel farther from the source

11. Electromagnetic Spectrum
Ch 18.2

12. Infrared rays can be felt by your skin, and can be very harmful
True
False
Statement
Radio waves include microwaves, tv, and radar waves- which have the longest wavelengths=low frequency
Infrared rays can be felt by your skin, and can be very harmful
Ultraviolet rays help your body produce vitamin D, which helps absorb Ca
Xrays are absorbed by bones and too much can kill living tissue
Gamma rays are used to kill cancer cells

13. Waves of the Spectrum Electromagnetic Spectrum Includes:
Full range of frequencies of electromagnetic radiation
Includes:

14. Radio Waves Longest wavelengths in the spectrum Lowest frequencies
300,000 MHz or less

15. Radio Waves Television Radio
Weather and location can affect reception of signal
Amplitude modulation (AM)
Amplitude is varied, frequency stays the same
Frequency modulation (FM)
Frequency is varied, amplitude stays the same

16. Radio Waves Microwaves Radar Radio Detection and Ranging
Doppler Effect
Radio waves are sent out, reflected, bounce back and picked up by a receiver
Shortest radio wave
Penetrate food only to a few centimeters
Also carry cell phone conversations

17. Infrared Rays Higher frequencies than radio
Lower than red light
Used as a source of heat or to detect heat differences
Can’t see it but can feel its warmth
Thermograms

18. Visible Light Ultraviolet Light Light that the human eye can see
Higher frequencies than violet light
In moderation
Help skin produce vitamin D, which helps absorb Ca
In excess
Causes sunburn, skin cancer, wrinkles
Kill microorganisims

19. X Rays
Gamma Rays
Very short wavelength, higher frequencies than ultraviolet
Bone and teeth
Absorb Xrays , show densities
Too much exposure
Kills living tissue
Shortest wavelengths, highest frequencies
Used to kill cancer cells, and take pictures of the brain
Overexposure
deadly

21. Behaviors of Light
Ch 18.3

22. Materials can be transparent, translucent or opaque
True
False
Statement
Materials can be transparent, translucent or opaque
Diffuse reflection is due to reflection off of a rough surface
A mirage is a false or distorted image due to reflection
Polarization waves vibrate in all direction unlike normal light that vibrates in one plane
Scattering of light is why the sky looks blue, clouds look white, and the sun setting looks red

23. Light and Materials Without light, nothing is visible
Transparent Material
Transmits light (light passes through)
Translucent Material
Scatters light
Can see through object, but looks cloudy
Opaque Material
Absorb or reflect light
No light passes through

24. Interactions of Light When light strikes a new medium the light can be
Reflected
Absorbed
Transmitted
Refracted
Polarized
Scattered

25. Interactions of Light Reflection Refraction Regular Reflection
Parallel light strikes a surface and reflect all in the same direction
Diffuse Reflection
Parallel light strikes a rough, uneven surface and reflect in many different direction
Cause mirages
False distorted images
Occur because
Light travels faster in hot air than cold

26. Interactions of Light Polarization Scattering
Light with waves that vibrate in only one plane
Light is redirected as it passes through a medium
Sunrise/Sunset
Tiny particles scatter blue light- you see the red light
Blue Sky
Blue light is scattered in all directions- blue sky even though colorless

28. Color
Ch 18.4

29. White light separates into the color spectrum(ROYGBIV)
True
False
Statement
White light separates into the color spectrum(ROYGBIV)
Color of an object depends only on what color of light shines on the object
Primary Colors of light at red, blue and green, while primary pigments are cyan, yellow and magenta
A primary color + a secondary color = white light
A pigment + a pigment = black pigment

30. White Light = Colors White light passes through a prism
Shorter wavelengths refract more than longer wavelengths
The colors separate
Process of white light separating into colors
Dispersion

31. Colors of Objects Color depends on What the object is made of
The color of light that strikes the object

32. Mixing Colors of Light Primary Secondary
Red, Green, Blue
If both light colors hit a surface, they mix to form a new color
Secondary
Cyan, Yellow, Magenta
Primary+Secondary=
White
Complimentary color of light

33. Mixing Pigments Pigment Primary Pigments 2 Pigments= Black
Reflects some colors
Absorbs some colors
Paints, inks, dyes, photos…
Primary Pigments
Secondary Colors
Cyan, Yellow, Magenta
2 Pigments= Black
Complementary Colors of Pigments

35. Sources of Light
Ch 18.5

36. A luminous object glows when light is shined on it
True
False
Statement
A luminous object glows when light is shined on it
An incandescent light (light bulb) has a filament, while a fluorescent light (energy efficient) has photons
A laser also has photons, but emits radiation
Neon lights color depends on the color of the tube
Sodium vapor and tungsten halogen lights are the same

37. Light Luminous Objects that give off their own light
Sun, flashlights, fireflies…

38. Types of Light Fluorescent Incandescent
Absorbs light at one wavelength, emits light at longer wavelength
Phosphor- solid that emits light by steadily emitting photons
Object gets hot enough to glow
Electrons flow through the filament of the bulb
The filament gets hot and emits light

39. Types of Light Neon Laser
Light Amplification by Stimulated Emission of Radiation
Generates a beam of coherent light
Solid, liquid or gas emits photons
Emit light when electrons move through a gas or mixture of gases inside glass tubing

40. Types of Light Sodium Vapor Tungsten Halogen
Solid sodium, with neon and argon gas
Electric current passes bulb, it ionizes, heats up and causes sodium to turn into a gas
Electrons flow through a tungsten filament, which gets hot and emits light