WHAT GOVERNS THE WAY THAT
GASES IN OUR ATMOSPHERE
BEHAVE?
CHARLES’ LAW
Molecules of gas at a fixed pressure and
temperature, vibrate sufficiently to
occupy a fixed volume
CHARLES’ LAW
Warm
CHARLES’ LAW
Increased molecular
vibration, spacing
increases
Warm
CHARLES’ LAW
Increased molecular
vibration, spacing
increases
Warm
Volume Increases
CHARLES’ LAW
Increased molecular
vibration, spacing
increases
Cool
Warm
Volume Increases
CHARLES’ LAW
Decreased molecular
vibration, spacing
decreases
Cool
Increased molecular
vibration, spacing
increases
Warm
Volume Increases
CHARLES’ LAW
Decreased molecular
vibration, spacing
decreases
Cool
Volume Decreases
Increased molecular
vibration, spacing
increases
Warm
Volume Increases
CHARLES’ LAW
“If the atmospheric pressure is held constant, hot gases expand to occupy
a bigger volume and cold gases contract to occupy a smaller volume.”
Decreased molecular
vibration, spacing
decreases
Cool
Volume Decreases
Increased molecular
vibration, spacing
increases
Warm
Volume Increases
CHARLES’ LAW
V=k2.T
At constant Pressure
Decreased molecular
vibration, spacing
decreases
Cool
Volume Decreases
Increased molecular
vibration, spacing
increases
Warm
Volume Increases
CHARLES’ LAW
V=k2.T
At constant Pressure
Decreased molecular
vibration, spacing
decreases
Cool
Increased molecular
vibration, spacing
increases
Warm
Volume Decreases
Volume Increases
V↓=k2.T↓
V↑=k2.T↑
BOYLE’S LAW
Molecules of gas at a fixed pressure and
temperature, vibrate sufficiently to
occupy a fixed volume
M =1.0
BOYLE’S LAW
Atmospheric Pressure
M =1.0
Vibrating molecules of gas
BOYLE’S LAW
Compress,
squeeze, add
“weight”
M =1.0
M = 0.5
M = 1.0
BOYLE’S LAW
Decompress,
relax, reduce
“weight”
Compress,
squeeze, add
“weight”
M = 0.5
M =1.0
M = 0.5
M = 1.0
Decreased Pressure
Volume expands
Increased Pressure
Volume contracts
BOYLE’S LAW
“At constant temperature, the pressure exerted on a gas is inversely related to the
volume the gas occupies – gases are compressible.”
M = 0.5
M =1.0
M = 0.5
M = 1.0
BOYLE’S LAW
P = k1/V
At constant Temperature
M = 0.5
M =1.0
M = 0.5
M = 1.0
P↓…. V↑
P↑ ….. V↓
HOW ARE THESE LAWS GOING TO
HELP TO MOVE MASS AND ENERGY IN
THE ATMOSPERIC SYSTEM?
EQUAL PRESSURE
(ATMOSPHERIC)
Air Filled Balloon
Higher
Pressure
Brick
Lower
Pressure
Air Flow
Differences in pressures cause
motion of the air
Air temperature ≈Sensible heat flux
from insolation
= f(latitude, season)
Changes in temperature
cause changes in volume
occupied by air.
Air temperature ≈Sensible heat flux
from insolation
= ∫ (latitude,season)
V=k2.T
At constant Pressure
Changes in temperature
cause changes in volume
occupied by air.
Air temperature ≈Sensible heat flux
from insolation
= ∫ (latitude,season)
V=k2.T
At constant Pressure
P = k1/V
At constant Temperature
Changes in volume occupied
cause changes in pressure on
air
Changes in temperature
cause changes in volume
occupied by air.
Air temperature ≈Sensible heat flux
from insolation
= ∫ (latitude,season)
V=k2.T
At constant Pressure
P = k1/V
At constant Temperature
Changes in volume occupied
cause changes in pressure on
air
Differences in pressure cause
movements within the
atmosphere
Changes in temperature
cause changes in volume
occupied by air.
Air temperature ≈Sensible heat flux
from insolation
= ∫ (latitude,season)
V=k2.T
At constant Pressure
P = k1/V
At constant Temperature
Changes in volume occupied
cause changes in pressure on
air
Differences in pressure cause
movements within the
atmosphere
Temporal and spatial
differences in insolation
related to pressure that
moves atmosphere
THE EQUATION OF STATE FOR AN
IDEAL GAS.
PUTTING IT ALL TOGETHER!
P = R. ρ. T
P = Pressure on a gas
R = Gas Constant
ρ = Density of gas
T = Temperature of gas
P = R. ρ. T
P = Pressure on a gas
R = Gas Constant
ρ = Density of gas
T = Temperature of gas
?
P = R. ρ. T
P = Pressure on a gas
R = Gas Constant
ρ = Density of gas: ρ = Mass/Volume
T = Temperature of gas
P = R. M/V. T
P = Pressure on a gas
R = Gas Constant
ρ = Density of gas: ρ = Mass/Volume
T = Temperature of gas
P = R. M. T
V
Charles’ Law: Fixed P, T and V directly related
9 = 1.
If T rises to 3.0, then
V must rise to 0.33 to
Keep P constant at 9!
9 = 1.
1 . 2.25
0.25
1 . 3.0
0.33
P = R. M. T
V
Boyle’s Law: Fixed T, P and V inversely related
Multiply both
sides by V
V . P = R. M. T
Pressure declines
so volume occupied
increases to keep
T constant
3. 3 = 1. 1. 9
4. 2.25 = 1. 1. 9
PRACTICAL APPLICATION
We know that Atmospheric Pressure declines with altitude, so what can we
expect to happen to Temperatures and the Density of the air as you climb a
mountain or go up in an airplane?
P = R. ρ. T
PRACTICAL APPLICATION
We know that Atmospheric Pressure declines with altitude, so what can we
expect to happen to Temperatures and the Density of the air as you climb a
mountain or go up in an airplane?
P = R. ρ. T
Should become colder and the atmosphere “thinner”!
PRACTICAL APPLICATION
We know that Atmospheric Pressure declines with altitude, so what can we
expect to happen to Temperatures and the Density of the air as you climb a
mountain or go up in an airplane?
P = R. ρ. T
Normal Lapse Rate: Rate at which temperatures decline (increase)
with increase (decrease) in altitude
PRACTICAL APPLICATION
We know that Atmospheric Pressure declines with altitude, so what can we
expect to happen to Temperatures and the Density of the air as you climb a
mountain or go up in an airplane?
P = R. ρ. T
Normal Lapse Rate: Rate at which temperatures decline (increase)
with increase (decrease) in altitude
6.5°C per Kilometer
3.6°F per 1000 ft.
MOUNT RANIER, WA.
4.392 km
-13°C
15°C
0 km
TACOMA, WA.