1. An Introduction to Waves and Wave Properties
Waves and Sound
An Introduction to Waves and Wave Properties

2. Announcements Sign in. Take a Packet and a Homework Sheet.
Turn in Post-Test from Modern Physics Exam.
Homework for this week is Waves and Sound #1

3. Animation courtesy of Dr. Dan Russell, Kettering University
Mechanical Wave
A mechanical wave is a disturbance which propagates through a medium with little or no net displacement of the particles of the medium.
Water Waves
Wave “Pulse”
People Wave
Animation courtesy of Dr. Dan Russell, Kettering University

4. Parts of a Wave crest : wavelength 3 equilibrium A: amplitude 2 4 6
x(m) -3
trough
y(m)

5. Speed of a wave
The speed of a wave is the distance traveled by a given point on the wave (such as a crest) in a given interval of time.
v = d/t
d: distance (m)
t: time (s)
v = ƒ
v : speed (m /s)
 : wavelength (m)
ƒ : frequency (s–1, Hz)

6. Period of a wave
T = 1/ƒ
T : period (s)
ƒ : frequency (s-1, Hz)

7. Wave Types
A transverse wave is a wave in which particles of the medium move in a direction perpendicular to the direction which the wave moves.
Example: Waves on a String
A longitudinal wave is a wave in which particles of the medium move in a direction parallel to the direction which the wave moves. These are also called compression waves.
Example: sound

8. Wave types: transverse

9. Wave types: longitudinal

10. Longitudinal vs Transverse

11. Other Wave Types Earthquakes: combination
(transverse “s-waves” and longitudinal “p-waves”)
Ocean waves: surface (transverse)
Light: electromagnetic (transverse)

12. Reflection of waves
Occurs when a wave strikes a medium boundary and “bounces back” into original medium.
Completely reflected waves have the same energy and speed as original wave.

13. Reflection Types
Fixed-end reflection: The wave reflects with inverted phase.
Open-end reflection: The wave reflects with the same phase
Animation courtesy of Dr. Dan Russell, Kettering University

14. Animation courtesy of Dr. Dan Russell, Kettering University
Refraction of waves
Transmission of wave from one medium to another.
Refracted waves may change speed and wavelength.
Refraction is almost always accompanied by some reflection.
Refracted waves do not change frequency.
Animation courtesy of Dr. Dan Russell, Kettering University

15. Constructive Interference

16. Destructive Interference