Focus : Waves

1. Focus: Waves Objective: Explain what transverse and longitudinal waves are, how they are alike and how they are different. We will be able to say how they occur in earthquakes.

2. Vocabulary to Know Examples: In the Ocean In the Clouds Earthquake

3. Sound waves are longitudinal. Longitudinal waves Transverse waves

4. Seismic waves are what we call the waves that happen during an earthquake. • When an earthquake happens, energy waves vibrates through the earth’s crust as the crust bends or breaks.

5. During an earthquake, there are both: • Transverse waves • Longitudinal waves

6. Which wave travels faster? Think-Pair-Share: • Think about the slinky • Let’s find out! • Human wave activity Since the energy is traveling the fastest way it can (in a straight line), the longitudinal wave is faster than the transverse wave. It gets from the force to the stopping point first. It is the first wave you feel in an earthquake. The transverse wave takes more time and energy to go perpendicular to the direction of the wave. You feel this wave second in an earthquake. It is sometimes called the “aftershock”.

7. Which wave does more damage? Think-Pair-Share: Write the questions and answer them in your interactive notebook. • Which wave do you think would do more damage to a city? Write this as a hypothesis. (“I think…because…” • Why do you think so? • Let’s find out! • Human wave activity with buildings

8. What are the parts of a wave? Transverse wave **WRITE THIS DOWN** The crest is the highest point on a transverse wave. The trough is the lowest point on a transverse wave. The rest position of the wave is called the node or nodal line.

9. **WRITE THIS DOWN** CREST TROUGH

10. What are the parts of a wave? Transverse wave **WRITE THIS DOWN** The wavelength is the distance from one point on the wave to the same point on the next wave.

11. SLINKY LAB

13. On a compressional wave the (**WRITE THIS DOWN**) area squeezed together is called the compression. The areas spread out are called the rarefaction. (**WRITE THIS DOWN**)The wavelength is the distance from the center of one compression to the center of the next compression. Compressional Longitudinal wave

14. SLINKY LAB

15. **WRITE THIS DOWN** The amplitude of a transverse wave is determined by the height of the crest or depth of the trough

16. **WRITE THIS DOWN** How high does it go? How low does it go?

18. What is wavelength? (**WRITE IT DOWN**) Wavelength is a measure of distance, so the units for wavelength are always distance units, such as meter, centimeters, millimeters, etc.

19. What is wave frequency? Frequency is the number of waves that pass through a point in one second. The unit for frequency is waves per second or Hertz (Hz). One Hz = One wave per second. (**WRITE THAT DOWN**) The smaller the wavelength, the more times it will pass through a point in one second. The larger the wavelength, the fewer times it will pass through a point in one second.

20. Focus: Waves Objective: Compare the properties of waves to the wavelike property of energy in earthquakes, light and sound. EQ:What are the 2 kinds of mechanical waves? How are they similar? How are they different?

21. WAVES

22. Vocabulary to Know Examples: In the Ocean In the Clouds Earthquake

23. Sound waves are longitudinal. Longitudinal waves Transverse waves

24. Seismic waves are what we call the waves that happen during an earthquake. • When an earthquake happens, energy waves vibrates through the earth’s crust as the crust bends or breaks.

25. During an earthquake, there are both: • Transverse waves • Longitudinal waves

26. Which wave travels faster? Think-Pair-Share: • Think about the slinky • Let’s find out! • Human wave activity Since the energy is traveling the fastest way it can (in a straight line), the longitudinal wave is faster than the transverse wave. It gets from the force to the stopping point first. It is the first wave you feel in an earthquake. The transverse wave takes more time and energy to go perpendicular to the direction of the wave. You feel this wave second in an earthquake. It is sometimes called the “aftershock”.

27. Which wave does more damage? Think-Pair-Share: Write the questions and answer them in your interactive notebook. • Which wave do you think would do more damage to a city? • Why do you think so? • Let’s find out! • Human wave activity with buildings

28. What are the parts of a wave? Transverse wave The crest is the highest point on a transverse wave. The trough is the lowest point on a transverse wave. The rest position of the wave is called the node or nodal line.

29. Vocabulary to Know CREST TROUGH

30. What are the parts of a wave? Transverse wave The wavelength is the distance from one point on the wave to the same point on the next wave.

32. Compressional Longitudinal wave On a compressional wave the area squeezed together is called the compression. The areas spread out are called the rarefaction. The wavelength is the distance from the center of one compression to the center of the next compression.

33. The amplitude of a transverse wave is determined by the height of the crest or depth of the trough

34. Vocabulary to Know How high does it go? How low does it go?

36. What is wavelength? Wavelength is a measure of distance, so the units for wavelength are always distance units, such as meter, centimeters, millimeters, etc.

37. What is wave frequency? Frequency is the number of waves that pass through a point in one second. The unit for frequency is waves per second or Hertz (Hz). One Hz = One wave per second. Wavelength and frequency are inversely related. The smaller the wavelength, the more times it will pass through a point in one second. The larger the wavelength, the fewer times it will pass through a point in one second.

38. Vocabulary to Know 3 3 How many crests? How many troughs? http://id.mind.net/~zona/mstm/physics/waves/introduction/introductionWaves.html

39. Waves have measurable properties

40. Frequency is the number of waves (vibrations) that pass through a point in one second. Period is the time it takes for one full wavelength to pass a certain point. Frequency is waves per second. Period is seconds per wave.

41. A wave moving through a medium travels at a certain speed. This is Wave Speed. Wave speed is usually measured in meters/second, but may be measured using other distance units (such as centimeters per second). How is Wave Speed calculated? Wave speed is calculated as the product of a waves frequency and wavelength. Wavelength is represented by the Greek letter lambda (λ) and frequency is represented by (f)

42. Vocabulary to Know 3 3 How many crests? How many troughs? http://id.mind.net/~zona/mstm/physics/waves/introduction/introductionWaves.html

43. Waves have measurable properties

44. Frequency is the number of waves (vibrations) that pass through a point in one second. Period is the time it takes for one full wavelength to pass a certain point. Frequency is waves per second. Period is seconds per wave.

45. A wave moving through a medium travels at a certain speed. This is Wave Speed. Wave speed is usually measured in meters/second, but may be measured using other distance units (such as centimeters per second). How is Wave Speed calculated? Wave speed is calculated as the product of a waves frequency and wavelength. Wavelength is represented by the Greek letter lambda (λ) and frequency is represented by (f)