The Nature of Sound

Question 1

what is sound?

Answer 1

a disturbance that results from any kind of movement, which creates changes in pressure in a medium.

these pressure changes are propagated through the medium to the ear

Question 2

what is air?

Answer 2

air is a gas made of molecules of various chemicals.

Question 3

what is brownian motion?

Answer 3

the random movement of molecules which causes them to collide.

molecules are never stationary except at absolute zero

Question 4

molecular collisions produce…

Answer 4

pressure!

Question 5

what is pressure?

Answer 5

the force acting perpendicularly on surface

force/area=pressure

greater area, less pressure
less area, more pressure

Question 6

english system measurements of pressure

Answer 6

pounds/square inch

Question 7

SI measurement of pressure (MKS)

Answer 7

force= Newtons
area= meters

pressure= N/meters squared = 1 pascal

Question 8

SI measurement of pressure (CGS)

Answer 8

force= dynes
area= centimeters

pressure= dynes/centimeters squared= 1 microbar

Question 9

how do you measure air pressure?

Answer 9

displacement of liquid in a U-tube

Question 10

how do you measure atmospheric pressure?

Answer 10

barometer!

Patmos is approx. 14.5 PSI or 100kPa

Question 11

what is aerodynamics?

Answer 11

the movement of air

Question 12

what is the most important constant about pressure of airflow?

Answer 12

it ALWAYS equalizes and moves from areas of HIGH to LOW pressure

this is different than brownian motion, although brownian motion is still occurring

Question 13

what is driving pressure?

Answer 13

the difference in pressure causing air to flow, only present when there is a pressure differential

Question 14

how is airflow measured?

Answer 14

liters or milliliters

Question 15

what is airflow?

Answer 15

organized movement of air through a particular area in a specific interval of time

Question 16

what is laminar flow?

Answer 16

parallel molecular motion, smooth flow, equal speed (calm river)

Question 17

what is turbulent flow?

Answer 17

obstructed, disturbed flow with random variations of pressure (river with rocks and trees)

Question 18

what is Boyle’s Law?

Answer 18

the inverse relationship between air volume and pressure

as volume increases, pressure decreases (VICE VERSA)

this allows for more area for the molecules to move around=less pressure generated

Question 19

how are density and pressure related?

Answer 19

density and pressure are directly proportional

the higher the density, the higher the pressure

(more tightly packed, more collision, more pressure?

Question 20

What is another name of relatively constant pressure?

Answer 20

ambient pressure

Question 21

Compression

Answer 21

areas of high pressure (when molecule A knocks into molecule B, density increases and pressure increases)

Question 22

Rarefaction

Answer 22

areas of low pressure ( A returns to its spot an keeps moving until elasticity pulls is back)

Question 23

elasticity

Answer 23

the property of an object to be able to spring back to its original size/form/location/shape after bring stretched/detached/displaced

Question 24

inertia

Answer 24

keeps an object stays in motion or at rest unless acted upon by an outside force

Question 25

hooke’s law

Answer 25

restoring force is proportional to the distance of displacement and acts in opposite direction ( the further something is pulls the greater the recoil force)

Question 26

friction

Answer 26

causes decreases in amplitude called damping

Question 27

wave

Answer 27

a disturbance that moves through a medium