1. What do all these pictures have in Common?

2. Chapter One, Section One
Waves
Chapter One, Section One

3. Waves Carry Energy
Waves are rhythmic disturbances that carry energy without carrying matter.

4. A model for waves
Think about the ripples made when you jump into water.
The energy carried by the ripples travels through the water.
The water molecules that make up the water pass the energy

5. A model for waves
The water molecules transport the energy in a water wave by colliding with the molecules around them.

6. Mechanical Waves
The types of waves that use matter to transfer energy are called Mechanical Waves
The matter through which a mechanical wave travels is called a medium.
Examples
Students passing the object
Water moving the energy

7. Mechanical Energy
Why do the astronauts have microphones?

8. Mechanical Energy
A mechanical wave travels as energy is transferred from one particle to another in the medium.
Examples:
Sound wave is a mechanical wave that can travel through the air as well as solids and liquids.
Without the medium for energy to travel through you would not hear sound.

9. Mechanical Waves
Mechanical Waves
Transverse Waves
Compressional Waves

10. Transverse Waves
In a mechanical transverse wave, the wave energy causes the matter in the medium to move up and down or back and forth at right angles to the direction of the wave.

11. Transverse Wave
As the energy moves through a transverse wave the matter does not move.
The waves have peaks and valleys at regular intervals.
High points of the wave = crests
Low points of the wave = troughs

12. Transverse wave

13. Compressional Waves
In a compressional wave, matter in the medium moves forward and backwards in the same direction that the wave travels.
A compressional wave is also known as a longitudinal wave .

14. Compressional Waves
Compressional waves carry only energy forward along the spring.
The area in which the wave is squeezed together is called compression
The area in which the wave is stretched apart is called rarefaction

15. Compressional Waves

16. Sound Waves Sound waves are compressional waves
Examples of sound waves:
Talking
Music coming out of the speaker
Drums
What do these examples have in common?
All waves are produced by something that is vibrating.

17. Making Sound Waves How do vibrating objects make sounds waves?
Drum Example:
When you hit the drum it starts vibrating up and down.
As the drumhead moves upward the molecules next to it are pushed closer together - compression
When the drumhead moves downward, the molecules have more room to spread farther apart – rarefaction
This series of compressions and rarefactions is called a sound wave.

18. Making Sound Waves

19. Chapter one, section two
Wave properties
Chapter one, section two

20. Amplitude
How high or low the wave rises or falls below the normal level is called the wave’s amplitude.
The amplitude is ½ the distance between the crest and the trough
In compressional waves, the amplitude is greater when the particles of the medium are squeezed closer together in the compression.

21. Amplitude

22. Amplitude and energy
A wave’s amplitude is related to the amount of energy that it carries with it.
Example:
Electromagnetic waves that make up bright light have greater amplitudes than the waves that make up dim light.

23. Amplitude and Energy Sound waves Greater amplitude = more energy
Loud sounds = greater amplitude= more energy
Soft sounds= lower amplitude = less energy
Greater amplitude = more energy
Lower amplitudes = less energy

25. Wavelength
For a transverse wave – wavelength is the distance from the top of one crest to the top of the next crest or the bottom of one trough to the bottom of the next trough.
For a compressional wave= wavelength is the distance between the centers of one compression to the center of the next compression, or the center of one rarefaction to the center of the next rarefaction.

27. Wavelength
Electromagnetic waves that range from kilometers to no less the diameter of an atom.

28. Frequency
Frequency of a wave is the number of wavelengths that pass a given point in one second
The unit of frequency is the number of wavelengths per second or hertz.
The faster the vibration is, the higher the frequency of the wave that is produced.

29. Frequency and wavelength
Longer wavelength
lower frequency
Short wavelength
Higher frequency
This is true for all waves that travel at the same speed

30. Color and pitch
The frequency and wavelength determine the color of visible light.

31. Color and pitch
In sound waves, either the wavelength or frequency determines the pitch.
The pitch is the highness or lowness of a sound.

32. Wave Speed
Mechanical waves (compressional and transverse) and electromagnetic waves move at different speeds through different materials.

33. Wave Speed Mechanical Waves
Mechanical waves travel faster in a medium in which atoms are closer together.
Which types of materials do mechanical waves travel best:
Solids
Liquids
gases

34. Wave Speed Electromagnetic Waves
Unlike mechanical waves, electromagnetic waves travel faster in a medium in which atoms are more spread out or not present.
Which types of materials do electromagnetic waves travel best:
Open space(no matter)
Gas
Liquids
Solids

35. Chapter one, Section Three
Wave Behavior
Chapter one, Section Three

36. Type of wave behaviors
Reflection
Refraction
Absorption

37. Reflection
Reflection occurs when a wave strikes a shiny object or surface and bounces off.
An echo is reflected sound.

38. Reflection An echo bounces off walls, ceiling, furniture, and people.
A reflection occurs when light waves bounce smooth, shinny surface.
Smooth surface = clear and sharp image
Uneven surface = unclear image ;l

39. Reflection
When light hits a smooth shiny surface, it is reflected at the same angle that it comes in.
Angle of incidence is the angle at which light strikes an object.
Angle of reflection is the angle at which light is reflected off an object.

40. Angle of incidence = Angle of reflection

41. Refraction
The bending of a wave as it moved from one medium to another is called refraction.
Refraction occurs when the speed of the wave changes as it passes from one substance to another.

42. Refraction and wave speed
A line that is perpendicular to the surface of the object is called the normal.
The larger the change in speed is the larger the change in direction.

43. Colors from refraction
Refraction causes prisms to separate sunlight into many different colors and produce rainbows

44. Absorption of light
When you shine light through a prism it a appears as a rainbow because white light is a mixture of all the colors that make up visible light.

45. Why do objects have color?
Why does grass look green or a rose looks red?
when a mixture of light waves strike an object that is not transparent, the object absorbs some of the light waves.
If an object looks red, it absorbs all the other colors of the spectrum and reflects red.
If the object appears black, it absorbs all the colors of the spectrum.

46. The Nature of Electromagnetic Waves
Chapter three, Section one

47. Electromagnetic waves
Transferring Energy
A wave transfer energy from one place to another without transferring energy
The sun is 92,960,000 miles away. How do the sun’s rays get to Earth if there is no matter to travel through?
Electromagnetic waves

48. Transferring energy
An electromagnetic wave is a wave that can travel through empty space and is produced by charged particles that are in motion.

49. Forces and Fields An electromagnetic wave is made of two parts:
An electric field
A magnetic field

50. electromagnetic waves
An electromagnetic wave is made of electric and magnetic fields.
Electromagnetic waves are produced by making charged particles, such as electrons, move back and forth causing them to vibrate.

51. Electromagnetic waves
A charged particle always is surrounded by an electric field.

52. Electromagnetic Waves
A charged particle that is in motion is also surrounded by a magnetic field.

53. How the waves are created
A charged particle vibrates by moving up and down or back and forth
It produces changing electric and magnetic fields that move away from the vibrating charge in many directions.
These changing fields traveling in many directions from an electromagnetic wave.

55. Wavelength and frequency
When the charge makes one complete vibration, one wavelength is created.
The frequency of an electromagnetic wave is the number of wavelengths that pass by a point in one second.

56. Radiant energy
The energy carried by the electromagnetic wave is called radiant energy
What happens if an electromagnetic wave strikes another charged particles?
The electric field of the wave exerts a force on the particle causing it to move

57. The Electromagnetic Spectrum
The wide range of electromagnetic waves with different frequencies and wave lengths is called the electromagnetic spectrum.

58. The Electromagnetic spectrum
All the waves in the electromagnetic spectrum are produced by electric charges that are moving or vibrating.
The faster charges vibrate, the higher the energy of the electromagnetic wave.

59. The Electromagnetic spectrum
Electromagnetic waves carry radiant energy that increases as the frequency increase

60. The difference between analog and digital signals

61. Analog vs. Digital

62. Analog vs. digital
Analog and digital signals are used to transmit information, usually through electric signals.
In both these technologies, the information, such as any audio or video, is transformed into electric signals

63. Analog vs. digital
In analog technology, information is translated into electric pulses of varying amplitude.
In digital technology, translation of information is into binary format (zero or one) where each bit is representative of two distinct amplitudes.

64. Analog Vs. digital Analog Digital
Technology - The analog sound wave replicates the original sound wave
Data Transmission – noise interference when sending signals
Examples – human voice, analog electric devices
Memory - Stored in the form of wave signal
Technology - Samples analog waveforms into a limited set of numbers and records them.
Data Transmission- No interference when sending signals
Examples- Computers, CDs, DVDs, and other digital electronic devices.
Memory- Stored in the form of binary bit

65. Analog vs. Digital

66. Analog vs. Digital

67. Advantages of digital signals
Signals do not get interference
Digital signals typically use less bandwidth. This is just another way to say you can cram more information (audio, video) into the same space.
Digital can be encrypted so that only the intended receiver can decode it ( secure telephone etc.)

68. What are some ways that you talk to your friends?

69. Telecommunications

70. Digital ways of communication
There are three primary ways in which information is shared digitally:
Radio waves
Fiber optic cables

71. Using Radio Waves
Radio waves are used to send and receive information over long distances.
Advantages of radio waves:
Pass through walls easily
Do not interact with humans
Not harmful to humans

72. Using Radio waves Objects that use radio waves to send information:
Cell phones
Blue tooth
Computers
iPads
Radio
GPS
……plus many more

73. Using fiber optics
Fiber optics works by sending information coded in a beam of light down a glass or plastic pipe
A fiber-optic cable is made up of 100 or more incredibly thin strands of glass or plastic known as optical fibers.

74. Using fiber optics
Fiber-optic cables carry information between two places using entirely optical (light-based) technology.
Hook your computer up to a laser, which would convert electrical information from the computer into a series of light pulses.
Fire the laser down the fiber-optic cable. After traveling down the cable at the speed of light, the light beams would emerge at the other end.
A photoelectric cell (light-detecting component) then turns the pulses of light back into electrical information his or her computer could understand.

75. Using fiber optics https://www.youtube.com/watch?v=9VmA2S2XiCo
Advantages of fiber optics
High capacity – transmits a lot more information
Less signal degradation
Uses less power
Uses light signals-means clearer transmission