1. Resonance
matching of forced vibration and natural frequency of an object, resulting in large amplitude of waves (standing wave + constructive interference from source)

2. Sound breaking wine glass video
Tacoma Narrows collapse video

3. Speed of Sound Sound waves travel through air at a speed of 343 m/s
Sound waves travel faster in denser materials, because sound waves are the longitudinal vibrations of molecules, so more molecules means faster transfer

4. Practice
v=λf This tuning fork that we used for the resonance demo has a printed frequency of X Hz. Let’s calculate the wavelength of the sound waves it produces. Now let’s compare that to the length of open space.

5. Resonance and Pipes
The wavelengths and frequencies of a sound can be determined by
The length of a “pipe”
If the pipe is “open” or “closed”

6. Open Pipes
Resonance occurs when antinodes are at the same distance as the pipe
Like waves with a
loose end

7. (One Side) Closed Pipes
Resonance occurs when antinodes are at the open end and nodes are at the closed end
Like waves with a
fixed end

8. A tuning fork oscillates with a frequency of 256 hertz after being struck by a rubber hammer. Which phrase best describes the sound waves produced by this oscillating tuning fork?
a)mechanical waves that require a medium for transmission
b)electromagnetic waves that require no medium for transmission
c)mechanical waves that require no medium for transmission
d)electromagnetic waves that require a medium for transmission

9. In a demonstration, a vibrating tuning fork causes a nearby second tuning fork to begin to vibrate with the same frequency. Which wave phenomenon is illustrated by this demonstration?
a) interference
b) Nodes
c) Resonance
d) the Doppler Effect

10. At an outdoor physics demonstration, a delay of 0
At an outdoor physics demonstration, a delay of 0.50 second was observed between the time sound waves left a loudspeaker and the time these sound waves reached a student through the air. If the air is at STP, how far was the student from the speaker?
a)1.5 x 108 m
b)1.5 x 10-3 m
c)1.7 x 102 m
d)6.6 x 102 m

11. Homework
Handout