2. So here we have a bunch of waves, also known as a wave train

3. Rest Position

4. crests

5. Crests: highest points of wave cycle from rest position

6. troughs Crests: highest point of wave cycle from rest position

7. Crests: highest points of wave cycle from rest position Troughs: lowest points of wave cycle from rest position

8. Amplitudes: max distance the wave vibrates from its rest position

10. amplitudes

12. Purple Amplitude: from rest position to crest Green Amplitude: from rest position to trough

13. Purple Amplitude: from rest position to crest Green Amplitude: from rest position to trough

14. amplitudes

16. Waves with larger amplitudes carry MORE energy than waves with smaller amplitudes

17. amplitudes

18. Wavelength: measured from one point on a wave to the same point on the next wave

19. amplitudes wavelength

20. amplitudes wavelength

21. amplitudes wavelength

22. amplitudes wavelength

23. All wavelength measurements are equal

24. Longer wavelengths carry LESS energy than shorter wavelengths Try it out with the slinkies at your rows. Does it take more or less energy to make waves with shorter wavelengths?

25. Changing a wave’s amplitude has NO effect on the wave’s wavelength

27. compression

28. Compression: point in the medium where molecules are close together

29. rarefaction Compression: point in the medium where molecules are close together

30. Rarefaction: point in the medium where molecules are far apart Compression: point in the medium where molecules are close together

31. Quick Lab Complete the worksheet from Friday

32. Exit Slip (Interactive Notebook) 1.What is the amplitude of a wave? 2.What is the wavelength? 3.TRUE or FALSE: A wave with a larger amplitude carries less energy. 4.Use the diagram to answer the following question. Which interval represents one full wavelength? A. Point A to Point C B. Point B to Point D C. Point A to Point G D. Point C to Point G

33. The frequency is… The number of waves produced in a given amount of time Count the number of crests/troughs that pass a point in a certain amount of time (transverse waves) Count the number of compressions/rarefactions that pass a point in a certain amount of time (longitudinal waves) Expressed in hertz (Hz) – One hertz = one wave per second (1 Hz = 1/s)

36. What are common units for length?

37. – Meter (m), inches (in)

38. What are common units for length? – Meter (m), inches (in), miles (mi) What are common units for mass?

39. What are common units for length? – Meter (m), inches (in), miles (mi) What are common units for mass? – Grams (g), pound (lb)

40. What are common units for length? – Meter (m), inches (in), miles (mi) What are common units for mass? – Grams (g), pound (lb) What are common units for time?

41. What are common units for length? – Meter (m), inches (in), miles (mi) What are common units for mass? – Grams (g), pound (lb) What are common units for time? – Seconds (s), minutes (min), hours (hr)

42. Units for Waves Wavelength  length (meter) Amplitude  length (meter) Frequency  Hertz (number of waves per second)

43. Higher frequency means… Shorter wavelength More energy Therefore, waves with shorter wavelengths carry MORE energy than waves with longer wavelengths Therefore, waves with lower frequency have ______ wavelengths and carry _____ energy

44. Higher frequency means… Shorter wavelength More energy Therefore, waves with shorter wavelengths carry more energy than waves with longer wavelengths Therefore, waves with lower frequency have longer wavelengths and carry less energy

45. The wave speed is… The speed at which a wave travels Speed = the distance traveled over time

46. Units for Waves Wavelength  length (e.g. meter) Amplitude  length (e.g. meter) Frequency  number of waves per second (e.g. 1/s) Wave speed  length per time (e.g. meter/second)

47. Quick Lab 1.Groups of about 4 students. 2.Send 1 group member up for supplies. 3.Tie the long string to the cabinet doors at the 8 labeled stations around the room. 4.Answer the Lab Questions in your Notebook.

48. What affects wave speed? The speed of a wave depends on the medium in which the wave is traveling For example, the wave speed of sound in air is about 340 m/s, BUT the wave speed of sound in steel is about 5,200 m/s The speed of a wave does NOT depend on the properties of the wave itself (e.g. amplitude, frequency, and wavelength)

49. Exit Slip (Interactive Notebook) 1.What is the frequency of a wave and what is its unit? 2.TRUE or FALSE: Waves with lower frequency have longer wavelengths and less energy. 3.What is wave speed? 4.What affects wave speed? a.Wave properties b.The medium c.Both wave properties and the medium d.Neither wave properties or the medium