1. Waves Have Measurable Properties
Ch. 15.2
Waves Have Measurable Properties

2. Vocabulary Crest – the highest point, or peak, of a wave
trough – the lowest point, or valley, of a wave
amplitude – the distance a medium travels above or below its position at rest
wavelength – the distance from one wave crest or trough to the next
frequency – the number of wavelengths passing a fixed point in a certain amount of time

3. Review Transverse waves – travel perpendicular to the disturbance
direction of disturbance
direction of wave
transfer of energy
Transverse waves – travel perpendicular to the disturbance
Longitudinal waves – travel in the same direction as the disturbance.
Longitudinal Wave
direction of disturbance
direction of wave
transfer of energy

4. Waves have amplitude, wavelength, and frequency
Common properties of waves that scientists measure:
Amplitude
Wavelength
Frequency

5. Crests and troughs Crests are the highest points or peaks of waves.
Troughs are the lowest points, or valleys of waves.
water level
at rest
fixed point
crest
trough

6. Waves have amplitude, wavelength, and frequency
a,b. Amplitude-distance between a line through the middle of a wave and a crest and a trough
c. Wavelength-distance from one wave crest to the next
d. Water level at rest
b(bottom). trough
a(top). Crest
Frequency – the number of waves passing a fixed point in a certain amount of time.

7. Amplitude 1. Wave with low amplitude 2. Wave with high amplitude
The wave with greater amplitude carries more energy

8. How Frequency and Wavelength are Related
When frequency increases, there are more waves per second, and the wavelength shortens. On the other hand, when frequency decreases, there are fewer waves per second, and the wavelength lengthens.

9. Graphing Wave Properties
Amplitude is measured by determining the compression of the medium
Frequency is measured by determining the number of waves passing a fixed point in a certain amount of time.

10. Graphing Wave Properties
For transverse waves, the amplitude is measured by determining the distance between the mediums position at rest and the wave’s crest or trough.
Frequency is measured in the same way for both types of waves.

11. Wave speed can be measured
The formula for wave speed is:
Speed = wavelength x frequency
Calculate the waves speed of a water wave that has a frequency of 5 waves per second and a wavelength 0.4m.

12. Wave speed can be measured
The formula for wave speed is:
Speed = wavelength x frequency
0.4 x 5 = 2.0 m/s