2007 - Week 1.2

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