Video Instruction

showmethephysics.com

Video

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

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

Heinrich Hertz was the first to send

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

• 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

2006 McGraw-Hill Higher Education

Enrichment

How the Ear Works

How Sound Works

Sound of a bell in a vacuum