Science 10 - Mr. Laura/ Ms. Reynolds
Name:_______________
Date:_______________
Fleetwood Park Secondary
Block:____
Section 10.2 Notes Atmospheric Pressure (p. 443- 446)
-
What is weather?
Weather is:

The ______________________________in a specific place and at a specific time
o Describes all aspects of the _______________, including:
 ______________________________
 ______________________________
 ______________________________
 ______________________________

Closely connected to _______________in the atmosphere because convection moves
______________________________throughout the troposphere,
o This causes the _______________we experience
-
Atmospheric Pressure
In general, Pressure= _______________/area
o Air pressure = ______________________________=
pressure exerted by the _______________about
any point on Earth’s surface.
o In other words, it is a measure how many air
molecules are colliding and exerting a
_______________ on you

Atmospheric Pressure is affected by these 3
factors:
o _______________
o _______________
o _______________
Measuring Atmospheric Pressure:

Is measured using a _______________which was invented by ______________________________
o He used an upside glass tube filled with _______________, and found that the
_______________of mercury changed (went up or down) with changes in weather

_______________atmospheric pressure made the mercury rise

_______________atmospheric pressure made the mercury fall
o Newer barometers are called: ______________________________

Contains a capsule of ______________________________

When the ____________________________changes, it causes the capsule to
expand or contract

The SI unit for atmospheric pressure = _______________ (Pa)
o 1 pascal = 1 N/m2 (_______________/area)
o Most measurements are given in kPa (kilopascals) = 1000 Pa
o At sea level, the atmospheric pressure is _______________, or _________/cm2 which is
similar to having ______ of air pushing down on each square centimetre of your body
Pressure is affected by altitude and temperature
Altitude

Increased altitude = _______________pressure

Decreased altitude = _______________pressure
Temperature
-

Increased temperature = ______________pressure

Decreased temperature = ______________pressure
Kinetic molecular theory says that as particles gain
______________________________, they move around
more quickly
o because the molecules take up ________space,
______________air = less dense than ______________air
Pressure is also affected by Humidity

______________- the measurement that describes the amount of ______________in the air.

Water molecules take up more space than ___________________________, but their mass is
less
o This makes them ______________dense

____________________________- humidity expressed as the number of grams of water vapour
in 1kg of air

____________________________- the point where air becomes saturated- it can’t hold any
more ______________at a certain ______________
o

When specific humidity= the ability of air to hold water
____________________________- compares the amount of water vapour in the air with the
amount that the air ______________hold if it was ____________________________
Read Pages 447 and 448, take some notes on your own. Try to explain High and Low pressure in
your own words.
Air Masses:
High Pressure systems:
Low Pressure Systems:
-
KEY
Section 10.2 Notes Atmospheric Pressure (p. 443- 446)
-
What is weather?
Weather is:

The condition of the atmosphere in a specific place and at a specific time
o Describes all aspects of the atmosphere, including:


Temperature

Atmospheric pressure

Amount of moisture in the air

Wind speed and direction
Closely connected to Heat transfer in the atmosphere because convection moves
air and thermal energy throughout the troposphere,
o This causes the weather we experience
-
Atmospheric Pressure
In general, Pressure= amount of force/area
o Air pressure = atmospheric pressure =
pressure exerted by the mass of air about
any point on Earth’s surface.
o In other words, it is a measure how many air molecules are colliding and exerting a
force on you

Atmospheric Pressure is affected by these 3 factors:
o Altitude
o Temperature
o Humidity
Measuring Atmospheric Pressure:

Is measured using a barometer, which was invented by Evangelista Torricelli
o He used an upside glass tube filled with mercury, and found that the height of
mercury changed (went up or down) with changes in weather

Increase atmospheric pressure made the mercury rise

Decrease atmospheric pressure made the mercury fall
o Newer barometers are called: aneroid barometers

Contains a capsule of flexible metal

When the atmospheric pressure changes, it causes the capsule to expand or
contract

The SI unit for atmospheric pressure = pascal (Pa)
o 1 pascal = 1 N/m2 (force/area)
o Most measurements are given in kPa (kilopascals) = 1000 Pa
o At sea level, the atmospheric pressure is
101.3 kPa, or 1 Kg/cm2 which is similar
to having 1kg of air pushing down on each
square centimetre of your body
Pressure is affected by altitude and temperature
Altitude

Increased altitude = decreased pressure

Decreased altitude = increased pressure
Temperature
-

Increased temperature = decreased pressure

Decreased temperature = increased pressure
Kinetic molecular theory says that as particles gain kinetic energy, they move around more
quickly
o because the molecules take up more space, warm air = less dense than cold air
Pressure is also affected by Humidity

Humidity- the measurement that describes the amount of water in the air.

Water molecules take up more space than oxygen and nitrogen, but their mass is less
o This makes them less dense

Specific Humidity- humidity expressed as the number of grams of water vapour in 1kg of
air

Dew point- the point where air becomes saturated- it can’t hold any more water at a
certain temperature
o

When specific humidity= the ability of air to hold water
Relative humidity- compares the amount of water vapour in the air with the amount that
the air could hold if it was totally saturated