1. Do Now… Explain the similarities of nuclear fission and nuclear fusion. What are their differences? Think of some long term effects that can be caused by nuclear reactions? 1

2. 2 Waves and Vibrations

3. Waves and vibrations Objective: I will be able to distinguish between the frequency, wavelength, and velocity of waves traveling in various media. 3

4. What caused this??? http://www.youtube.com/v/-5fKvN- RwKs http://www.youtube.com/v/-5fKvN- RwKs 4

5. 5 What is a wave? a wave is a disturbance that travels through a medium from one location to another. a wave is the motion of a disturbance

6. 6 Waves are everywhere in nature Sound waves, visible light waves, radio waves, microwaves, water waves, sine waves, telephone chord waves, stadium waves, earthquake waves, waves on a string, slinky waves

7. Slinky in action http://www.youtube.com/v/X1OGiWPq5j8 http://www.youtube.com/v/cSqLXVmtVkc 7

8. Do Now… List some types of waves around you right now. Explain what is the propagation source of these sound waves and what medium they are traveling through. 8

9. 9 Slinky Wave One way to do this is to jerk the slinky forward the beginning of the slinky moves away from its equilibrium position and then back. the disturbance continues down the slinky. this disturbance that moves down the slinky is called a pulse. (this is called the propagation) if we keep “ pulsing ” the slinky back and forth, we could get a repeating disturbance.

10. 10 Slinky Wave Let ’ s use a slinky wave as an example. When the slinky is stretched from end to end and is held at rest, it assumes a natural position known as the equilibrium or rest position. To introduce a wave here we must first create a disturbance. We must move a particle away from its rest position.

11. 11 Slinky Wave This disturbance would look something like this This type of wave is called a LONGITUDINAL wave. The pulse is transferred through the medium of the slinky, but the slinky itself does not actually move. It just displaces from its rest position and then returns to it. So what really is being transferred?

12. Slinky Video demonstrating Transvers and longitudinal waves http://www.youtube.com/v/y7qS6SyyrFU 12

13. 13 Slinky Wave Energy is being transferred. The metal of the slinky is the MEDIUM in that transfers the energy pulse of the wave. The medium ends up in the same place as it started … it just gets disturbed and then returns to it rest position. The same can be seen with a stadium wave.

14. Sound waves http://www.youtube.com/v/GkNJvZINSEY 14

15. Learning Check… 1) What are forms of waves? a) lightb) earthquake c) Sound waves 2) The “pulse” that creates the wave is called the _______________. 3) Does the particles of the medium (substance) move along with the transverse wave. a) trueb) false 4) The medium particles will go back to their original place. a) trueb) false 15

16. Learning Check… 1) What are forms of waves? a) lightb) earthquake c) Sound waves 2) The “pulse” that creates the wave is called the propagation. 3) The particles of the medium (substance) move along with the transverse wave. a) trueb) false 4) The medium particles will go back to their original place. a) trueb) false 16

17. 17 Longitudinal Wave The wave we see here is a longitudinal wave. The medium particles vibrate parallel to the motion of the pulse. This is the same type of wave that we use to transfer sound. Can you figure out how?? show tuning fork demo

18. Benchmark Makeup…Oct 17 If you scored 3.5 or lower and wish to make up the Benchmark grade you may do so by writing a essay on the following subjects: Nuclear energy in the world today. How does it work and the environmental impact upon the world. Nuclear medicine and ways it is used to help people in the world today. Must be 2 type written full pages (3 handwritten) Must have a title page with your name Must have a bibliography page (3 sources) 18

19. Do Now… List the differences between longitudinal waves and transverse waves. State some examples of each different type of wave. 19

20. 20 Transverse waves A second type of wave is a transverse wave. We said in a longitudinal wave the pulse travels in a direction parallel to the disturbance. In a transverse wave the pulse travels perpendicular to the disturbance.

21. 21 Transverse Waves The differences between the two can be seen

22. 22 Transverse Waves Transverse waves occur when we wiggle the slinky back and forth. They also occur when the source disturbance follows a periodic motion. A spring or a pendulum can accomplish this. We can calculate the frequency by seeing how many cycles of the wave for a given length of time pass through a given point.

23. Transverse wave video http://www.youtube.com/v/ubRlaCCQfDk 23

24. Wave Demostration… http://phet.colorado.edu/sims/html/wave- on-a-string/latest/wave-on-a- string_en.html http://phet.colorado.edu/sims/html/wave- on-a-string/latest/wave-on-a- string_en.html 24

25. Learning Check… 1) Longitudinal waves move particles up and down? a) true b) false 2) _________ waves move the particles back and forth but will come to rest in the original position. 3) Transverse waves move particles back and forth. a) trueb) false 4) Sound waves are longitudinal waves. a) trueb) false 25

26. Learning Check… 1) Longitudinal waves move particles up and down? a) true b) false 2) Longitudinal waves move the particles back and forth but will come to rest in the original position. 3) Transverse waves move particles back and forth. a) trueb) false 4) Sound waves are longitudinal waves. a) trueb) false 26

27. Do Now… Explain how the frequency of a wave determines the strength of the wave. Explain how the amplitude of a wave determines the strength of the wave. 27

28. 28 Anatomy of a Wave Now we can begin to describe the anatomy of our waves. We will use a transverse wave to describe this since it is easier to see the pieces.

29. 29 Anatomy of a Wave In our wave here the dashed line represents the equilibrium position. Once the medium is disturbed, it moves away from this position and then returns to it

30. 30 Anatomy of a Wave The points A and F are called the CRESTS of the wave. This is the point where the wave exhibits the maximum amount of positive or upwards displacement crest

31. 31 Anatomy of a Wave The points D and I are called the TROUGHS of the wave. These are the points where the wave exhibits its maximum negative or downward displacement. trough

32. 32 Anatomy of a Wave The distance between the dashed line and point A is called the Amplitude of the wave. This is the maximum displacement that the wave moves away from its equilibrium. Amplitude

33. 33 Anatomy of a Wave The distance between two consecutive similar points (in this case two crests) is called the wavelength. This is the length of the wave pulse. Between what other points is can a wavelength be measured? wavelength

34. 34 Anatomy of a Wave What else can we determine? We know that things that repeat have a frequency and a period. How could we find a frequency and a period of a wave?

35. Learning Check… 1)What is point A called __________? 2)What is the dotted line __________? 3)The point D to I is called the ________. 4)Point D is called the _________. 5)Point A to F is called the _________. 6)The height of a wave is called _________? 35

36. Learning Check… 1)What is point A called Crest? 2)What is the dotted line equilibrium? 3)The point D to I is called the wavelength. 4)Point D is called the trough. 5)Point A to F is called the wavelength. 6)The height of a wave is called amplitude? 36

37. Reading Check… Go to Luskinacademy.org and to the chemistry reading tab. Open up chemistry reading and click on the left side for “Waves and their Applications in Technologies”. You will click on the reading section “types of waves” Once finished you will answer the questions 1 and 2 with complete sentences. 37

38. 38 Wave frequency We know that frequency measures how often something happens over a certain amount of time. We can measure how many times a pulse passes a fixed point over a given amount of time, and this will give us the frequency.

39. 39 Wave frequency Suppose I wiggle a slinky back and forth, and count that 6 waves pass a point in 2 seconds. What would the frequency be? 3 cycles / second 3 Hz we use the term Hertz (Hz) to stand for cycles per second.

40. 40 Wave Period The period describes the same thing as it did with a pendulum. Watch the teacher demo. It is the time it takes for one cycle to complete. It also is the reciprocal of the frequency. T = 1 / f f = 1 / T

41. 41 Wave Speed We can use what we know to determine how fast a wave is moving. What is the formula for velocity? velocity = distance / time What distance do we know about a wave wavelength and what time do we know period

42. 42 Wave Speed so if we plug these in we get velocity = length of pulse / time for pulse to move pass a fixed point v = / T we will use the symbol to represent wavelength

43. 43 Wave Speed v = / T but what does T equal T = 1 / f so we can also write v = f velocity = frequency * wavelength This is known as the wave equation.

44. Learning Check… 1)The ________ is the amount of time it takes a wave to complete one cycle. 2) What is the formula for velocity? _________ a) v = mab) v = d/Tc) v = d x T 3) What is the formula for wave speed? _______ 4) The formula for frequency is ________. a) f = T/1b) v = 1/Tc) f = 1/T 44

45. Learning Check… 1)The frequency is the amount of time it takes a wave to complete one cycle. 2) What is the formula for velocity? _________ a) v = mab) v = d/Tc) v = d x T 3) What is the formula for wave speed? v = / T 4) The formula for frequency is ________. a) f = T/1b) v = 1/Tc) f = 1/T 45

46. 46 Wave Behavior Now we know all about waves. How to describe them, measure them and analyze them. But how do they interact?

47. 47 Wave Behavior We know that waves travel through mediums. But what happens when that medium runs out?

48. 48 Boundary Behavior The behavior of a wave when it reaches the end of its medium is called the wave ’ s BOUNDARY BEHAVIOR. When one medium ends and another begins, that is called a boundary.

49. 49 Fixed End One type of boundary that a wave may encounter is that it may be attached to a fixed end. In this case, the end of the medium will not be able to move. What is going to happen if a wave pulse goes down this string and encounters the fixed end?

50. 50 Fixed End Here the incident pulse is an upward pulse. The reflected pulse is upside-down. It is inverted. The reflected pulse has the same speed, wavelength, and amplitude as the incident pulse.

51. 51 Fixed End Animation

52. 52 Free End Another boundary type is when a wave ’ s medium is attached to a stationary object as a free end. In this situation, the end of the medium is allowed to slide up and down. What would happen in this case?

53. 53 Free End Here the reflected pulse is not inverted. It is identical to the incident pulse, except it is moving in the opposite direction. The speed, wavelength, and amplitude are the same as the incident pulse.

54. 54 Free End Animation

55. 55 Change in Medium Our third boundary condition is when the medium of a wave changes. Think of a thin rope attached to a thin rope. The point where the two ropes are attached is the boundary. At this point, a wave pulse will transfer from one medium to another. What will happen here?

56. 56 Change in Medium In this situation part of the wave is reflected, and part of the wave is transmitted. Part of the wave energy is transferred to the more dense medium, and part is reflected. The transmitted pulse is upright, while the reflected pulse is inverted.

57. 57 Change in Medium The speed and wavelength of the reflected wave remain the same, but the amplitude decreases. The speed, wavelength, and amplitude of the transmitted pulse are all smaller than in the incident pulse.

58. 58 Change in Medium Animation Test your understanding

59. Learning Check… The way a wave behaves once it reaches the end of the medium is called the____________. 2) In a free end medium, the wave is ________ back along the medium source. 3) In a fixed end medium, the wave is _________ back along the medium source. 4) In a wave passes along a thick rope to a smaller rope the wave is _______ in size. In addition, a _________ wave in reflected. 59

60. Learning Check… The way a wave behaves once it reaches the end of the medium is called the boundry behavior. 2) In a free end medium, the wave is reflected back along the medium source. 3) In a fixed end medium, the wave is inverted back along the medium source. 4) In a wave passes along a thick rope to a smaller rope the wave is larger in size. In addition, a inverted wave in reflected. 60

61. 61 Wave Interaction All we have left to discover is how waves interact with each other. When two waves meet while traveling along the same medium it is called INTERFERENCE.

62. 62 Constructive Interference Let ’ s consider two waves moving towards each other, both having a positive upward amplitude. What will happen when they meet?

63. 63 Constructive Interference They will ADD together to produce a greater amplitude. This is known as CONSTRUCTIVE INTERFERENCE.

64. 64 Destructive Interference Now let ’ s consider the opposite, two waves moving towards each other, one having a positive (upward) and one a negative (downward) amplitude. What will happen when they meet?

65. 65 Destructive Interference This time when they add together they will produce a smaller amplitude. This is know as DESTRUCTIVE INTERFERENCE.

66. Learning Check… 1) Destructive interference can cause waves to be canceled out? a) trueb) false 2) ___________ interference is when smaller waves will add together to become a larger wave. 3) When two waves travel along the same medium it is called __________. 3) Destructive interference will have one amplitude that is negative and one that is positive. a) trueb) false 66

67. Learning Check… 1) Destructive interference can cause waves to be canceled out? a) trueb) false 2) Constructive interference is when smaller waves will add together to become a larger wave. 3) When two waves travel along the same medium it is called interference. 3) Destructive interference will have one amplitude that is negative and one that is positive. a) trueb) false 67