1. QOD: What two factors affect velocity of waves?
Wave Properties
QOD: What two factors affect velocity of waves?

2. Wave Characteristics Waves transfer energy from one place to another
does work on anything in its path
reflect off boundaries

3. Vocabulary (Write on the left side)
a wave is a ripple in space & time
Crest – High point of a wave
Trough – Low point of a wave
Amplitude – Distance from the midpoint to the crest or trough of the wave. Determined by the energy of the wave.
Wavelength – Distance from crest to crest or trough to trough

4. *Draw the following on your left-side – your “activity” side
*The greater the amplitude, the more energy the wave has.

5. Frequency - # of waves that pass a given point in a given amount of time (period)
Frequency = 1 / period
f = 1 / p or p = 1/ f

6. Units Frequency measured in hertz – Hz
Period measure in seconds/cycle (s/c)
As wavelength decreases, frequency increases

7. Which has the larger wavelength?
Which has the greater frequency?

8. 1. A hummingbird beats its wings up and down with a frequency of 80
1. A hummingbird beats its wings up and down with a frequency of 80.0 Hz. What is the period of the hummingbird's flaps?

9. 2. Taylor jumps up and down on a trampoline with a frequency of 1.5 Hz. What is the period of Taylor's jumping?

10. Velocity of a Wave
Depends on the material (or medium) that the wave is passing through
velocity = wavelength X frequency
v =  X f
 = meter (centi or milli)
F = hertz (Hz)
V = m/s

11. Velocity Comparisons
Sound travels at about 340 m/s through air, but travels about 4 times faster in water
Velocity of electromagnetic waves = 3.0 X 108 m/s

13. Electromagnetic & Radio Waves QOD: Which type of waves can travel the longest and why?

14. 2 Major Types of Waves 1. Electromagnetic Waves
Travel at the speed of light: 3 X 108 m/s
Type of wave depends on the wavelength
Radio – longest electromagnetic wavelengths, least energy
Gamma – shortest wavelength, most energy

15. Electromagnetic Spectrum

16. All Electromagnetic Waves travel at the speed of light: 3.0 X 108 m/s

17. 2 Types of Radio Waves AM – Amplitude Modulated
Radio waves are generated by changing the amplitude of the wave
Measured in kHz (kilohertz)
What frequency would 1340 AM be equal to in Hz
FM – Frequency Modulated
Radio waves generated by changing frequency
Measured in MHz (megahertz)
What frequency would 99.7 FM be equal to in Hz

18. Radio station WKLB in Boston broadcasts at a frequency of 99. 5 MHz
Radio station WKLB in Boston broadcasts at a frequency of 99.5 MHz. What is the wavelength of the radio waves emitted by WKLB?

20. 4. In California, John is surfing on a wave that propels him toward the beach with a speed of 5.0 m/s. The wave crests are each 20. m apart, a) What is the frequency of the water wave? b) What is the period?

21. 5. Renee is told by her doctor that her heart rate is 70
5. Renee is told by her doctor that her heart rate is 70.0 beats per minute. If Renee's average blood flow in the aorta during systole is 1.5 X m/s, what is the wavelength of the waves of blood in Renee's aorta, created by her beating heart?

22. 6. Dogs are able to hear much higher frequencies than humans are capable of detecting. For this reason, dog whistles that are inaudible to the human ear can be heard easily by a dog. If a dog whistle has a frequency of 3.0 X 104 Hz, what is the wavelength of the sound emitted?

23. 7. While flying to Tucson, Colton's plane experiences turbulence that causes the coffee in his cup to oscillate back and forth 4 times each second. If the waves of coffee have a wavelength of 0.1 m, what is the speed of a wave moving through the coffee?

24. 8. Radio station KSON in San Diego broadcasts at both 1240 kHz (AM) and 97.3 MHz (FM). a) Which of these signals, AM or FM, has the longer wavelength? b) How long is each?