1. Properties of Waves Amplitude, Wavelength, Frequency, Speed

2. Slide 1 Main Idea How to draw wave diagrams How to draw wave diagramsDetails Draw a transverse wave like a wavy rope Draw a transverse wave like a wavy rope Draw a longitudinal wave like spring (slinky) stretching and compressing Draw a longitudinal wave like spring (slinky) stretching and compressing

3. Slide 2 Main Idea What is amplitude What is amplitudeDetails Amplitude is the maximum distance of the medium particles from REST to CREST Amplitude is the maximum distance of the medium particles from REST to CREST Draw a straight line down the middle of the wave, half-way between Crest and Trough. This is the Rest position Draw a straight line down the middle of the wave, half-way between Crest and Trough. This is the Rest position More amplitude takes more energy More amplitude takes more energy

4. Slide 4 Main Idea What is amplitude of transverse waves? What is amplitude of transverse waves?Details Distance from REST to CREST –or- REST to TROUGH Distance from REST to CREST –or- REST to TROUGH

5. Slide 4 Main Idea What is amplitude of Longitudinal waves? What is amplitude of Longitudinal waves?Details Amplitude is how compressed or rarefied the medium is. Amplitude is how compressed or rarefied the medium is. One compression to another is like one crest on a transverse wave One compression to another is like one crest on a transverse wave

6. Slide 4 Main Idea What is wavelength What is wavelengthDetails Distance between two corresponding parts of a wave Distance between two corresponding parts of a wave Transverse – Crest to Crest –or- Trough to Trough Transverse – Crest to Crest –or- Trough to Trough Longitudinal- Compression to Compression Longitudinal- Compression to Compression

7. Slide 4 Main Idea What is frequency? What is frequency?Details Frequency is number of waves that pass a point in one second Frequency is number of waves that pass a point in one second Measured in HERTZ (one hertz=one wave per second) Measured in HERTZ (one hertz=one wave per second)

8. Slide 4 Main Idea What is speed? What is speed?Details Speed is how far a wave travels in one unit of time (distance/time) Speed is how far a wave travels in one unit of time (distance/time) Speed = wavelength x frequency Speed = wavelength x frequency Frequency=speed/wave length Frequency=speed/wave length Wavelength=speed/fre quency Wavelength=speed/fre quency

9. How fast do waves move?

10. Period The time it takes for 1 wave to pass by, measured in seconds

11. Frequency The number of waves that pass by in 1 second

12. Frequency is measured in Hertz Hz = 1 Second

14. Frequency = 1 Period

15. Example: A wave passes by every 2 seconds Period = 2 s Frequency = ½ = 0.5 Hz

16. Wave Speed The speed at which a wave passes through a medium

17. Wave speed = Frequency x wavelength (Hz) (m) Unit for speed is m/s

18. Example 1 How fast is a wave moving that has a frequency of 5 Hz and a wavelength of 0.5 m?

19. Speed = Frequency x Wavelength Speed = 5 Hz x 0.5 m Speed = 2.5 m/s

20. Example 2 A wave passes by every 3 seconds and the distance between each crest of the wave is 5 meters. What is the speed of the wave?

21. Period = 3 seconds Frequency = 1/3 = 0.33 Hz Wavelength = 5 m Speed = 0.33 Hz x 5 m Speed = 1.65 m/s

22. Example 3 A mosquito makes a sound by beating its wings 600 times every second. If the sound waves move at 340 m/s, what is the wavelength of the sound waves?

23. Speed =freq.x wavelength 340 m/s = 600 x wavelength Wavelength = 0.57 m