Transcript Standard EPS Shell Presentation

Foundations of
Physical Science
Workshop: The Loop Track
Sound & Waves
CPO Science
Key Questions
 What are some important qualities of
waves?
 What is resonance and why is it
important?
 What is sound and how do we hear it?
 What is music and how do we make
music?
Overview
 Why learn about waves?
 Make waves on a string
 Make sound waves
 Make musical sound
Basic characteristics of waves
Frequency
 “how often” (cycles/sec,
wiggles/sec, ) Hertz
Wavelength

Length of one
wave (“S” shape)
Basic characteristics of
waves
 Node
 Points where the string
does not move
 Anti-node
 Points where the string
moves the most
Common Uses for Waves
 Radio waves are used to carry
signals over large distances
 Ultrasound uses very high
frequency sound waves to make
images of the inside of the body
 Light is a wave that has different
frequencies we call colors
Set up a Wave Experiment
 Attach Wiggler to bottom of Stand
 Attach Fiddlehead to top of Stand
 Attach elastic string to Fiddlehead and
Wiggler
 Connect black cord from Wave machine to
Wiggler
 Connect Wave machine to Timer
Change The Frequency
 Observe the string as you change the
frequency
 Describe What Happens
Patterns on the String
Standing
Wave
Patterns
OBSERVATONS
 The string vibrates
 Standing Wave patterns appear at some
frequencies
 All of these frequencies are multiples of
the lowest one that produces this effect
 The frequency multiplied by the
wavelength of each standing wave is
the same for all of the waves
RESONANCE
 A Condition where a Driving Force or push
occurs at a frequency that results in a
Standing Wave
 These Standing Waves occur at what are
called Natural Frequencies or Harmonics
 Every object, substance and material has
its own Natural Frequencies, where they
“like” to vibrate
 All Natural Frequencies are multiples of the
Fundamental
FREQUENCY x WAVELENGTH
 Each Harmonic has a different frequency and
wavelength
 Frequency x Wavelength gives the same answer
for ALL Harmonics
 Cycles/Seconds x Meters/Cycle= Meters/Second
which is a value for speed of the Wave on the
string
 If Frequency increases, Wavelength decreases and
if Frequency decreases, Wavelength increases
Sound Waves
 How do we perceive Sound Waves?
 What do they have in common with
other kinds of waves?
 What is different about Sound Waves?
Set Up a Sound Experiment
 Disconnect the Wiggler from the
Sound and Waves Machine
 Connect Mini-Speakers to the Sound
and Waves Machine
 Switch the CPO Timer II to Sound
Mode
Tuning Notes for Chords
Note Name
C
D flat
D
E flat
Frequency
264
Yes
Yes
297
D major
Yes
317
330
F
352
G flat
380
G
396
A flat
422
B flat
C minor
285
E
A
C major
Yes
Yes
Yes
Yes
Yes
440
Yes
475
B
495
C
528
Optional
Optional
Sound and Music - Chords
 Different notes have different
frequencies
 Chords are combinations of different
notes with specific mathematical
relationships
 Different relationships of the notes will
produce chords with very different
“moods” or “feel”
Sound and Music - Beats
 Small Difference in Frequency
 Product of Interference
The Musical Scale
 Mathematical Relationships in the form of
Ratios
1 9/8 5/4 4/3 3/2 5/3 15/8 2
DO RE MI FA SO LA TI DO
264 297 330 352 396 440 495 528
C D E
F
G
A
B
C
Palm Pipes
 Check to see the note of your palm pipe
 Follow along with the music and play
your palm pipe when your note occurs.
 How could pipes that have the same note
be different lengths?
 Can you tell what key each song is in?
Note Name
Key Color Frequency
C
528
B
495
B flat
A
475
440
A flat
422
G
396
G flat
380
F
352
E
330
E flat
D
D flat
C
317
297
285
264
Musical Instruments
 Musical instruments play different
notes
 Frequencies are controlled by
altering wavelength
 Vibrating materials like strings or
reeds cause chunks or columns of
air to vibrate
Musical Instruments
 Natural Frequencies/Harmonics cause
amplification through Resonance
 Instruments can be amplified this way
and/or electronically
 The vibrating element vibrates at ALL its
Harmonics, not just the Fundamental.
 The combination of these frequencies
give an instrument its particular sound.
HAPPY BIRTHDAY
Melody C C D C F E
Harmony
A
A Bb
Melody C C C A F E D
Harmony
F
C Bb
C C D CGF
Bb
B A
b
Bb B b A F G F
C
A
TWINKLE,TWINKLE
LITTLE STAR
F F C C D D C
Bb Bb A A G G F
Harmony C C A A Bb Bb A
G G F F E E C
C C Bb Bb A A G
C C Bb Bb A A G
Harmony A A G G F F C
A A G G F F C
Melody
F F C C D D C
Bb Bb A A G G F
Harmony C C A A Bb Bb A
G G F F E E C
Melody
Melody
GOD BLESS AMERICA
Melody F E D E D C
GF G A
Harmony A C
E D E F
Melody
Harmony
E
Bb A C F G A
C
G A Bb D
D
G F G F E F
F
E
C
Melody E F G C
F GA C
G A Bb E A Bb C
Harmony C
D
E
E
F
Melody
D C Bb A G F
Bb A G F
Harmony
F F E CE D
F F E C
G C
G