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2007 - Week 1.2. Some Fundamental Items from PHYSICS. Assignment-. Begin reading the Background Notes that are posted on the website. Roughly pages 1-18. From Our Discussion. Elements of Music Structured/Designed Sound Some pleasant – bells, most musical instruments Some nasty – whip - PowerPoint PPT Presentation
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2007 - Week 1.2
Some Fundamental Items from
PHYSICS
Assignment-
Begin reading the Background Notes that are posted on the website.
Roughly pages 1-18
From Our Discussion
Elements of Music Structured/Designed Sound
Some pleasant – bells, most musical instruments Some nasty – whip Some intermediate - drums
Rhythm (time) Tones (Not defined, though) Loudness Pleasurable ???? Message ???? Must there be one? What Kind?
Bone Flute – Music is older than I am!
50,000 years or moreNeanderthal
reconstructions
Where did instruments come from???
What does this mean?
Lightening
Takes time to get to you or you are in big trouble. Speed = distance/time What is distance? What is time?
Sound --- A “disturbance”
Important Definitions
Length or Distance How “far” something moves or travels. Measured against some agreed upon standard.
Length Standard .. The Gorf
Unknown Length
1 2 3 4 1/8
= 4 1/8 Gorfs
The real standard:
Systems of Units SI Units …. Meters, Seconds,
Newtons/Kilograms English System ….. Feet/yards,
seconds, pounds/poundals
More Important Definitions
TIME The subjective “distance” between two EVENTS.
It needs to be objective … ie measurable and reproducible.
Original Clock – The Earth’s Rotation“It is two days journey”
Today’s Clocks – “He ran the race in 4 hours, 2 minutes and 21.85
seconds”
Things that “tick” at some rate
The planet … once a day The Pendulum .. Depends on a number of
things; Parameters:
Length
Weight,whateverthat is.
Mounting
In case you care…..
2/32
1415926.3
(g)
(L) 2
sftg
gravityofonaccelerati
Lengthperiod
We will discuss this “g-thing” when weget to acceleration.
Sun Clock
Water Clocks
And so on …
Rolex (~$10K) Atomic Clock (NASA) $ megabucks
The music clock: the Metronome
112 quarter notes per minute.
Kind ofPendulum
We hear music (and other noise) in our brains.
Sound
And you didn’t even know that you have one!
Sound Waves push againstyour
Tympanic MembraneWhat is a wave, what is a push??
Inside your head
To Brain
d
D
In order to understand musical tones and their relationship to each other, we need to understand
GRAPHS!
A graph … what does it all mean?
time (seconds)2
dist
ance
(m
eter
s)
1
100
50
snail
rabbit
Speed
distance that travel toit takes time
traveleddistanceSpeed
So….
time (seconds)2
dist
ance
(m
eter
s)
1
100
50
snail
rabbit
Snail goes 100 meters in2 seconds …
Speed=100m/2s
Speed = 2 meters/second
Notice
spd
x timespeed distance
,time
distancespeed
then
if
Also
Velocity is speed in a particular direction. Velocity: 120 m/hr NORTH Speed: 120 m/hr (or mph)
Example
Sound travels about 1100 ft per second. How much time does it take for sound to
travel about 1 mile?
sec5~1100/5280/
vdt
vtd
Another Graph .. a biggy!
-1.5
-1
-0.5
0
0.5
1
1.5
0 5 10 15 20 25
Time (seconds)
dis
turb
an
ce
Important Definitions
Tf
or
periodfrequency
1
1
The PERIOD, T is the time it takes to go from one condition to the next time that exact condition is repeated.The frequency, the number of oscillations per second, is given by:
-1.5
-1
-0.5
0
0.5
1
1.5
0 5 10 15 20 25
Time (seconds)
dis
turb
an
ce
6 sec
Period = 6 secondsFrequency=1/6 per sec (Hz) =0.16 sec = 160 ms
Siren … a scientific instrument
The Graph
-0.2
0
0.2
0.4
0.6
0.8
1
1.2
0 2 4 6 8 10 12
Time in milli-seconds
"air
spee
d"
- re
lati
ve
100 Bottles of beer on the wall …
Resonance (later)
Rotational Speed
(Turns/second)
Loud
ness
Helmholtz Resonators
Helmholtz’s Results
Note from Middle C Frequency
C 264
D 297
E 330
F 352
G 396
A 440
B 496