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Critical Application Questions for Unit 8 – Sound & Waves
DIRECTIONS: Research and report on the following items. Focus on the physics principle which controls the
condition and describe in detail the reason for the condition. You must cite the source of your answer in MLA
format (i.e. textbooks, URL, etc.). Write each question and answer on a separate sheet of paper. A complete
answer must include (1) a description of the condition; (2) an explanation of the physics principle applied, (3) at
least one contributing diagram; and (4) citation of your sources. You can receive up to 2 extra credit points for
each completed answer. Incomplete answers will receive less credit. No submissions will be accepted after April
27, 2011. Good Hunting!
A. One of the pieces of evidence to support an expanding universe is the red shift caused by the Doppler Effect. Describe in detail
how this theory is supported by the Doppler Effect.
B. The human hearing frequency range is approximately 20 Hz to 20000 Hz. Find three animals which can hear above 20000 Hz and
three which can hear below 20 Hz and describe in terms of their aural anatomy why they can hear these frequencies while humans
can not.
C. There is a variety of security keys used to keep unauthorized people from accessing secure environments such as passwords, metal
keys, and even human finger prints. One such technology is voice recognition keys. Explain how voice recognition keys work and
its strengths and weaknesses.
D. You are walking to an out door concert which has already begun at a local park. As you are walking, the first sound you notice is
the bass guitar and drums. Next you notice the muddled vocal sounds and the rhythm section. As you approach the park, the
cymbals and the female singers are added to the sounds. Explain why the sounds are noticeable to your ears in the order
described.
E. Its New Year’s Day and you and your friends are taking your first trip to Philadelphia to see the Mummers. After a lot of
searching, you finally find a parking space on the street 3 blocks from Broad Street where the Mummers are performing. As you
are walking towards Broad Street, you can hear the bass instruments like the drums and baritone saxophones. As you turn the
corner, your can see the colorful costumes and the entire sound of the string band ca be heard. Explain why you could only hear
the bass instruments before turning the corner to Broad Street?
F. Explain in detail how scientists determine the epicenter of earthquakes using S and P waves.
G. Explain in detail how noise-canceling headphones work in terms of constructive and destructive interference.
H. Our auditorium contains several systems to control or modify the sound generated by the performers on stage. List all of the
obvious systems and describe their function or purpose.
I. The following are various ear disorders which can impair hearing. Select any 5 disorders and describe the nature of the disorder.
Large vestibular aqueduct
Acoustic neuroma
Perforated/ruptured ear drum
syndrome
Autoimmune inner ear disease
Pressure sores on the ear
Mastioditis
Barotrauma
Sensorineural deafness
Meniere’s disease
Blockage in the ear canal
Surfer’s ear
Otosclerosis
Cholesteatoma
Tinnitus
Otitis externa
Hyperacusis
Usher’s syndrome
Otitis media
Labyrinthitis
Vertigo
J. Explain how amplifiers make sounds louder electrically as compared to the process used by an old fashion mega-phone.
K. In Mythbusters fashion, find out wether it is true that a desperado could hear if the posse was getting closer by placing his ear to the
ground and listing for the pounding of the horse hooves or was this just an old wives tale.