chapter 3 section 2
Terms in this set (36)
why does air have mass?
because air in the atmosphere consists of atoms and molecules
Because air has mass, it also has other properties including _________ & ______________.
density and pressure
the amount of mass in a given volume of air
how do you calculate air density?
by dividing its mass by its volume
is the atmosphere light or heavy
the force pushing on an area or surface
is the result of the weight of a column of air pushing on an area
the wieght of a column of air weighs as much as a ?
why doesn't air pressure crush us?
the reason is that the molecules in air push in all directions
normal air pressure at sea level?
760 mm of mercury or 30 inches
3 types of barometers:
1. mercury barometer 2. aneriod barometers 3. electronic barometers
air pressure changes how often
densier air exerts _____ pressure than less densier air
is an instrument that is used to measure air pressure
conistst of a long glass tube that is closed at one end and open at the other
how does the mercury barometer work?
open end rests in a dish of mercury. closed end is almost like a vaccuum . The air pressing down on the surface of the mercury in the dish is equal to the pressure exterted by the wieght of the column of mercury in the tube . (when air pressure increases, it presses down more on the surface of the mercury. greater air pressure forces the column of mercury higher)
what does aneroid mean
has an airtight chamber. the chamber is sensitive to changes in air pressure. when air pressure increases, the thin walls of the chamber are pushed in . WHen pressure drops, the walls bulge out.
use a computer chip to measure pressure
the pressure of the atmosphere is equal to ?
national weather service maps indicate air pressure using ?
one inch of mercury is equal to about
30 inches of mercury is about
the distance above sealevel/elevation
air pressure _____ as altitude _____> As air pressure _____, so does _.
decreases, increases, decreases, density
as you go up thru the atmosphere, the density of air ?
when density increases, the number of molecules in a volume?
one force affecting an object is air pressure, which is?
the result of the weight of a column of air pushing on an area
why can an aneriod barometer measure elevation as well as air pressure?
higher, you go up, pressure decreases
if there are more molecules in a given volume, the density is? If there are fewer molecules in a given volume, then density is?
air has properties such as?
density and pressure
a denser substance has ___ mass per unit volume than a _____ dense one.
most weather reports for the general public use ______ of mercury.
sea level has the weight of the ________ pressing on it.
the whole atmosphere
gas molecules are ____ apart at higher atitudes than at sea level.
air is ________ at higher altitudes