1. Warm-Up 11/15/13
Use the first few minutes to finish yesterday’s lab (only 5-10 minutes!)

2. Wave Properties Section 17.2 11/15/13

3. Parts of a Transverse Wave
Crests=high points
Troughs=low points
Amplitude=crest or trough to rest position
Wavelength=distance between 2 identical spots

4. Parts of a Compressional Wave
Compression=dense region
Rarefaction=less dense region
Amplitude=how dense compressions are
Wavelength=distance between 2 identical spots

5. Do the following in your notes:
Which has the longest wavelength? Highest amplitude?
Which has a shorter wavelength? Smallest amplitude?

6. Frequency and Period
Frequency=the number of wavelengths that pass a point every second. (rate of vibration of source)
Unit=Hertz (Hz)
1Hz means one wavelength passes per second
Period=time for one wavelength to pass a point

7. Wavelength and Frequency
As frequency increases, wavelength decreases
As frequency decreases, wavelength increases

8. Amplitude and Energy
The greater the amplitude (height or density) the more energy the wave carries

9. Your Job

10. Wave Properties: Speed

11. Objectives Identify what affects the speed of waves
Calculate wave speed using frequency and wavelength

12. What Affects wave speed?
The medium
Sound is faster in liquids & solids
Light is faster in gases and empty space
The temperature
Sound is faster in warmer temps

13. What affects wave speed cont.
Why do you think this is?
Sound waves rely on matter colliding with other bits of matter
Solids/liquids have matter closer together
Heat makes atoms move faster
Light is not mechanical
Matter blocks light waves!

14. Calculating Wave Speed
Equation: ν=f λ
ν is wave speed (velocity, m/s)
f is frequency (Hz, 1/s)
λ is wavelength (m)

15. Example
What is the speed of a sound wave that has a wavelength of 2.00m and a frequency of Hz?
Identify the variables: f=170.5 Hz and λ=2.00m
Plug into the equation: ν=f λ so ν=(170.5Hz)(2.00m)=( /s)(2.00m)
Solve: ν=341 m/s

16. Your Job