Video Instruction

showmethephysics.com

 

 

Sound Needs a Medium

Video

Wave Characteristics

[ HTML5 ]

Show Me The Physics Website

 

 

This movie is part of the collection: Prelinger Archives

Production Company: ERPI Classroom Films, Inc. Distributed by Encyclopedia Britannica
Audio/Visual: sound, B&W
Creative Commons license: Public Domain

School blocks YouTube? Use link below.

SoundF_WL_Amplitude2.mp4

 

 

 

 

 

What is this speaker component called?

What kinds of waves does it produce?

High or low frequency?

 

 

 

 

 

Woofer, Outputs low frequency waves

 

 

 

 

II. Characteristics of Periodic Waves

 

A. Frequency(f) = #vibrations/sec

 

 

= # Cycles/# sec

 

 

= Hertz (Hz)

Source: Elroy M. Avery School Physics
(New York: Sheldon and Company, 1895) 202

Clipart ETC

 

hertz

Heinrich Hertz was the first to send
and receive radio waves.

 

 

 

 

 


Frequency

 - Determined by

Source
of Wave,

Not Medium

 

Cycle = (single vibration) 

 

 

 

Ex)

How many cycles between the dots?

 

 

 

3 Cycles

 

 

 

 

 

 

 

Ex) 10 cycles pass a fixed point in a wave train in 5 seconds.
What is the frequency of the wave?

 

f = 10 cycles =  2 cycles 
5 seconds 1 sec

 

 

f = 2 Hertz (Hz)

 

 

 

 

Top View of a Wave

[ HTML5 ]
St. Mary's Physics Online

 

 

 

 

 

 

 

Sound Waves
David Kirby - U. of Calif.

 

 

 

 

 

Top view of a periodic wave
(Each line is a crest)

 

 

 

 

 

 

Crest
Physics 2000

 

 

 

 

 

 

Review - Longitudinal or Transverse?

[ Flash ]

 

 

 

Ex) A wave generator operating for
4 seconds
produces the waves drawn below.

Top view of a periodic wave
(Each line is a crest)

 

How many waves are drawn between A and B? (Be careful!!)

What is the frequency of this
periodic wave train?

 

 

8 cycles

 

 

 

f = 8 cycles/4 sec

 

 

 

f = 2 cycles/sec 

 

 

 

Ex) 2 cycles pass a fixed point in a wave train in 10 sec.

What is the frequency ?

 

 

 

f = # Cycles/# sec

 

 

 

f = 2 Cycles/10 sec

 

f = .2 Hz

• Sound, frequency is pitch.

 

Source: Elroy M. Avery School Physics
(New York: Sheldon and Company, 1895) 247

Clipart ETC

 

• Light, frequency is color.

 

 

 

Human Ear:

Frequency Range

 

 20 Hz - 20,000 Hz.

 

 

Did you know dogs are

capable of hearing

higher pitch sounds

than humans? 







 

 

The range of frequencies you
can hear changes with age. 

How old are you?

 

How to get rid of teenagers 

 

School blocks YouTube? Download link below.

CBC - Moving Sound Technologies.mov

Ringtones the old folks can't hear

Ear Animation

2006 McGraw-Hill Higher Education


 

megahertz

 

 

 

 

 

Enrichment


How the Ear Works

 

How Sound Works

NASAconnect

 

Sound of a bell in a vacuum

| Onsite Version |

UC Irvine Physics and Astronomy Videos

 


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Established 1995
Use any material on this site (w/ attribution)