Air Pressure
mercury barometer
barometer in which changes in air pressure are measured by changes in the height of the column above mercury in the dish.
(cold or warm) air is associated with low air pressure.
warm
HIGH pressure = _______ weather
"fair"
LOW pressure = ________ weather
"stormy"
atomic mass of Hydrogen atom
1 amu
atomic mass of nitrogen atom
14 amu
atomic mass of oxygen atom
16 amu
standard air pressure at sea level
29.92 in Hg OR 1,013 mb
What is the air pressure at the summit of Mt. McKinley?
525 mb
What is the elevation of Mt. McKinley?
6193 m
Air density changes with:
ALTITUDE, TEMPERATURE, HUMIDITY
humidity
Air pressure decreases as the humidity of air increases.
In which state is Mt. McKinley located?
Alaska
Humid Air
As less massive water vapor molecules are added to air, the humidity of this air will increase; As humidity of air increases, the density of air becomes less and air pressure becomes lower.
As air humidity INCREASES, air density DECREASES and air pressure
DECREASES
As air temperature INCREASES (gets warmer), air density
DECREASES
As air temperature INCREASES, air density DECREASES and air pressure
DECREASES
As altitude INCREASES, air density DECREASES and air pressure
DECREASES
As altitude above Earth's surface INCREASES, air density
DECREASES
As the density of air DECREASES, air pressure
DECREASES
As the water vapor in air (humidity) INCREASES, air density
DECREASES
Air pressure changes with
DENSITY, ALTITUDE, TEMPERATURE, HUMIDITY
warm air mass results in:
Faster particle movement; Particles farther apart; Lower density because less mass in a set volume; RESULTS IN LOWER AIR PRESSURE.
effects of altitude increasing
Gas particles become fewer and more spread-out; There is less mass within a set volume, so air density decreases; Because there is less mass of air pushing down, air pressure decreases as you go upwards in the atmosphere.
As air humidity DECREASES, air density INCREASES and air pressure
INCREASES
As air temperature DECREASES (gets colder), air density
INCREASES
As air temperature DECREASES , air density INCREASES and air pressure
INCREASES
As altitude DECREASES, air density INCREASES and air pressure
INCREASES
As altitude above Earth's surface DECREASES, air density
INCREASES
As the density of air INCREASES, air pressure
INCREASES
As the water vapor in air (humidity) DECREASES, air density
INCREASES
cold air mass results in:
Slower particle movement; Particles closer together; Higher density because more mass in a set volume; RESULTS IN HIGHER AIR PRESSURE.
Dry Air
With little or no water vapor molecules in air, the humidity of air is very low; As the humidity of air decreases, the density of air increases and air pressure becomes higher.
altitude
air pressure decreases as altitude increases.
millibars (mb)
air pressure units recorded by an aneroid barometer.
air pressure is greatest...
at the surface
aneroid barometer
barometer that is a cylinder with an internal spring; All air is removed, so cylinder is a vacuum; A needle and gauge on the outside are connected to the spring to record changes in air pressure; Increase in air pressure compresses the cylinder and spring resulting in the needle moving CLOCKWISE; Decrease in air pressure expands the cylinder and spring, resulting in the needle moving COUNTER CLOCKWISE
(cold or warm) air is associated with high air pressure.
cold
Air pressure __________ as altitude increases
decreases
Air pressure is greatest closer to the surface where the air is
denser
in mercury barometer, mercury _______ to indicate decrease of air pressure
falls
pressure
force acting on a set area
What force keeps 99% of the gases in the atmosphere close to Earth's surface?
gravity
barometer
instrument used to measure changes in air pressure
Air containing water vapor has ____ mass than dry air.
less
humid air is ____ dense and exerts a ______ air pressure than dry air.
less
Air pressure is lower, high in the atmosphere where the air is
less dense
Warm air is __________ than cold air.
less dense
Cold air is __________ than warm air.
more dense
air pressure
pressure caused by the weight of the atmospheric gases pushing down on the surface of the Earth OR any object in the atmosphere.
in mercury barometer, mercury _______ to indicate increase of air pressure
rises
inches of mercury (Hg)
the height of the column of mercury when using a mercury barometer.
In which layer of the atmosphere are most of the gases found?
troposphere