1. Electromagnetic Waves

3. Electromagnetic Waves- transverse waves consisting of changing electric fields and changing magnetic fields
Electric Field- a region of space exerts electric forces on charged particles
Magnetic Field- a region of space produces magnetic forces

4. If one changes the other changes so they regenerate each other
Electromagnetic waves are produced when an electric charge vibrates or accelerates

5. Electromagnetic waves can travel though a vacuum, or empty space, as well as through matter!

6. Electromagnetic radiation- transfer of energy by electromagnetic waves traveling through matter or across space

7. Thunder and Lightning

8. Speed of Light
Albert Michelson ( )- American physicist who first measured the accurate speed of light.

9. All electromagnetic waves travel at 3.00x108 m/s

10. The only difference in electromagnetic waves is their wavelength and frequency
Remember: v=λf

11. Wave or Particle?
Electromagnetic radiation behaves sometimes like a wave and sometimes like a stream of particles.

12. Evidence for the Wave Model
Thomas Young ( )- English physicist

13. Evidence for the Particle Model
Albert Einstein ( )
Proposed that light, and all electromagnetic radiation, consists of packets of energy called photons
Photoelectric effect- emission of electrons from a metal caused by light striking the metal

15. Intensity
Intensity- the rate at which a wave’s energy flows through a given unit of area
The intensity of light decreases as photons travel farther from the source.

16. Wavelength Range
Frequency Range
Common Uses
Interesting Information

18. Behavior of Light Light and Materials
Materials can be transparent, translucent, or opaque

19. Transparent
A material through which you can see clearly; transmits light, which means it allows most of the light that strikes it to pass through

20. Translucent
A material that scatters light; makes objects look fuzzy or unclear

21. Opaque
Either absorbs or reflects all of the light that strikes it; you cannot see through these objects

22. Interactions of Light
When light strikes a new medium, the light can be reflected, absorbed, or transmitted.
When light is transmitted, it can be reflected, polarized, or scattered

23. Reflection
Image- a copy of an object formed by reflected (or refracted) waves of light
Regular reflection- occurs when parallel light waves strike a surface and reflect all in the same direction (smooth polished surface)
Diffuse reflection- when parallel light waves strike a rough, uneven surface, and reflect in many different directions

25. Refraction Bending of waves as it passes through a new medium
Mirage- a false or distorted image caused by hotter air above the surface refracting light waves; often looks like water

26. Polarization
Polarized light- light with waves that vibrate in only one plane
Polarized sunglasses have vertical polarized filters so that horizontal polarized light is blocked reducing glare

27. Scattering- light is redirected as it passes through a medium

28. COLOR

29. Separating White Light Into Colors
White sunlight is made up of all the colors of the visible spectrum
As white light passes through a prism, shorter wavelengths refract more than longer wavelengths and the colors separate
Dispersion- process in which white light separates into colors
Red- longest wavelength- least bent
Violet- shortest wavelength- bent most

30. Double Rainbow

31. The Colors of Objects
The color of any object depends on what the object is made of and on the color of light that strikes the object.
Pigment- material that absorbs some color of light and reflects others
Photography Link

32. Secondary Colors- Combination of 2 primary colors
Primary Colors- 3 specific colors that can be combined in varying amounts to create all possible colors
In Light: Red, Green, and Blue
In Pigment: Cyan, Magenta, and Yellow
Secondary Colors- Combination of 2 primary colors
In Light: Cyan, Magenta, and Yellow
In Pigment: Red, Green, and Blue

33. Complimentary Colors
In Light: Any two colors that combine to make white
In Pigment: Any two colors that combine to make black

34. The Law of Reflection
Ray diagram- shows how rays changed direction when they strike mirrors and pass through lenses.

36. Virtual image- a copy of an object formed at a location from which light rays appear to come
Remember: rays do not actually come from behind the mirror!

37. Concave Mirrors
Concave Mirrors- when the inside surface of a curved mirror is the reflecting surface
Focal point- the point at which the light rays meet
Real image- a copy of an object formed at the point where light rays actually meet
Can be viewed on a surface such as a screen
Concave mirrors can form either real or virtual images
When the object is farther from the mirror than the focal point, the reflected rays meet in front of the mirror
When the object is closer to the mirror than the focal point the reflected rays spread out and appear to come from behind the mirror

39. Convex Mirrors
Convex mirrors- when the outside surface of a curved mirror is the reflecting surface
Convex mirrors always cause light rays to spread out and can only form virtual images

40. Lenses Light travels at 3.00 x 108 m/s in a vacuum.
As it passes through new media it slows down
Air- almost 3.00 x 108
Water x 108
Glass x 108

41. When light enters a new medium at an angle, the change in speed causes the light to bend or refract

42. Lens- Object made of transparent material that has one or two curved surfaces that can refract light
Concave lens- curved inward at the center and is thickest at the outside edges
Concave lenses always cause light rays to spread out and can only form smaller virtual images
Convex lens- curved outward at the center and is thinnest at the outer edge
Convex lenses form either real or virtual images

43. Convex lens
Concave lens