1. TOPIC: Energy
AIM: Describe waves.
Do Now: (Take out your waves reading notes)
Review Question #1 on back of KE and PE reading notes
HW: CL Energy due Monday!

2. If both of these balls are traveling down a bowling lane at the SAME speed, which one would have more kinetic energy? Support your answer.

3. Wave
Traveling disturbance that carries energy from one place to another
REPEATING disturbance

4. A pebble tossed into the water will create a circular disturbance which travels outwards in all directions. The pebble transfers some of its energy to nearby water molecules causing them to move. These water molecules transfer this energy to molecules around them…Energy is traveling in the form of a wave on the surface of the water.

5. There is a great amount of energy in these waves hitting the shore.

6. Cause of waves =
VIBRATIONS

7. Slinky waves can be made by vibrating the coil back & forth in either a horizontal or a vertical direction.

8. A tuning fork forces air particles to vibrate creating sound.

9. A wave is the movement of energy from a vibrating source.

10. Matter waves travel through:
MEDIUM

11. Medium for the following waves:
Ocean waves =
water

12. Sound waves =
air

13. Mechanical Require a medium waves Ex: Sound waves
Sound can’t be heard in outer space
Why???
Bc outer space is a vacuum

14. The sound produced by the bell cannot be heard since sound can’t travel through a vacuum. It is a mechanical wave.

15. Ex : light & radio waves, x-rays
Medium not needed
CAN TRAVEL THROUGH A VACUUM (no matter exists)
Ex : light & radio waves, x-rays
Electromagnetic
waves

17. Vacuum
Region where no matter exists
Example: outer space

18. Normal resting position

19. Crest
Trough

20. Crest – high points
Trough – lowest points

22. Amplitude

23. Amplitude – height Distance from crest/trough to rest
High amp = a lot of energy

26. Wavelength – distance bw 2 crests or 2 troughs

27. Wavelength
Wavelength

31. # of complete waves per unit of time
Frequency

35. Can you see the difference between these two waves
Can you see the difference between these two waves? Hint…look at the movement of the particles.

36. Transverse Waves

37. Particles of medium move at RIGHT ANGLES to direction of the wave
(PERPENDICULAR)
Direction of particles
Direction of wave

40. Ex: Ocean Waves, waves on a rope

41. Longitudinal waves
(Compressional waves)

42. Particles of medium move PARALLEL to the direction of the wave
(BACK AND FORTH)
Direction of particles (left & right)
Direction of wave

44. Parts of a longitudinal wave

45. rarefaction
compression

46. compression = where particles are close together
rarefaction = where particles are far apart
rarefaction
compression

48. Ex: Sound waves

55. Forces in Earth’s crust can cause regions of the crust to shift, bend, or even break. The breaking crust vibrates, creating seismic waves that carry energy outward. Seismic waves are a combination of compressional and transverse waves. They can travel through Earth and along Earth’s surface. The more the crust moves during an earthquake, the more energy is released.

56. Let’s summarize…
What is a wave?
Describe the cause of waves.
Describe a medium.
Identify an example of a medium.
Describe a vacuum.
How do particles move through a medium?
Explain the difference between mechanical and electromagnetic waves.
Explain the difference between transverse and longitudinal waves.

57. Any substance through which a wave can travel is called a
solid 
vacuum   
medium 
liquid

58. Waves transfer
energy
matter
particles
heat

59. Which of the following is the best example of a wave?
A stone rolling downhill
A vehicle moving on a bumpy road
A string vibrating on a guitar
A grasshopper jumping up and down

60. Which of the following statements applies to longitudinal waves?
The motion of the medium is random.
The motion of the medium is in a circular pattern.
The motion of the medium is parallel to the motion of the wave.
The motion of the medium is perpendicular to the motion of the wave.

61. Sound reaches our ears because sound makes particles
heat up.
slow down.
cool down.
vibrate.

62. The distance between the Earth and the moon was determined by measuring the time it took for light waves from the Earth to travel to the moon and back. Why was it not possible to use sound waves for this experiment?
Sound waves must move through a substance.
Sound waves change frequency on the return to earth.
Sound waves move too slowly for this technique to be accurate.
Sound waves move more slowly in the Earth’s atmosphere than in space.

63. A large spring is stretched horizontally between 2 people
A large spring is stretched horizontally between 2 people. One person wiggles the spring up and down at one end. The up-and-down vibration then moves along the spring on to the other person. Which of the following type of wave is created in the spring?
pressure wave
longitudinal wave
transverse wave
nonmechanical wave