Transcript Technology and Weather

Technology and
Weather
Air Pressure
Air Pressure
The force of air against Earth’s surface
gas
particles
Earth
gravity
Air pressure and a hot air balloon
faster
farther
apart
lowers
low
Hint to help remember…I feel low/sad when
it’s cloudy +/or precipitating.
slow
closer
denser
higher
high
Hint for remembering: I’m Happy
when skies are clear and fair.
down
Think back to convection
currents.
 Why do warm molecules rise and
cooler molecules sink?
 Warm molecules are less dense so they rise
up. As they rise up, they cool, become more
dense, and therefore sink.
So what is wind???
Wind Song
 The reasoning of less dense molecules rising helps
explain how wind is formed. Like other gases, air
higher density to a region of
moves from a region of _______
lower
high _________
pressure
_______
density. Cold, _____
moves in to
replace the warmer, rising air. The air moving from
wind
high to low pressure areas is called ______.
Sea Breeze
Land Breeze
Sea and Land Breezes
night
 A land breeze occurs during the ______;
a water (sea)
day
breeze occurs during the _______.
land
 Air flows from land to water in a ________
breeze; air
flows from water to land in a ______
breeze.
sea
 Land and water breezes can be found on the shores of
lakes
large _________
and _________,
as well as along
rivers
seacoasts/oceans.
 Sea and Land Breezes Demo
Land heats
and cools
faster than
water!!
Global Winds
 Winds that blow across long distances in predictable
patterns.
 They carry air masses from one region to another.
 Each winds always blows in the same direction.
 Global winds do not flow straight, they curve because
Earth is rotating. coriolis effect

http://www.classzone.com/books/earth_science/terc/content/visualizations/es1904/es1904page01.cfm
 Global Winds in the United States (prevailing
westerlies) move weather from the West to the East
Polar Easterlies
 Wind belts that extend from the
poles to 30° latitude
 These winds move cold air from
both poles toward the equator.
Westerlies
 Wind belts found between 30°
and 60° latitude
 Blow towards the poles from
west to east carrying moist air
over the Unites States
Trade Winds
Winds that blow from 30°
almost to the equator
Warm air from the equator
moves at high altitudes over
oceans. There it cools,
descends, and begins to flow
back toward the equator.
Doldrums
Located along the equator
where no winds blow
because the warm rising air
creates an area of low
pressure. As air rises and
cools near the equator, water
vapor condenses causing it to
rain almost everyday near the
equator.
Global Winds
Question 1
What causes winds?
Answer
Winds are caused by the
uneven heating of Earth’s
surface, which causes
pressure differences
Question 2
What are the three types of
global winds?
Answer
Polar Easterlies
Westerlies
Trade Winds
Question 3
What is the difference
between a land breeze and a
sea breeze?
Answer
Sea breezes occur during the
day when the land is warmer
than water and a land breeze
occurs at night when the
water is warmer than land
Weather Game…
Temperature
Air Pressure
Density
H
H
H
L
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Temperature and Humidity
 Water evaporates when it changes
liquid
gas
from a _____to
a _____.
Humidity is
moisture in the air in the form of a
water
vapor
gas called ______
______.
Water
vapor comes from any source from
evaporates
which water ________
into the air.
 When the air has more water vapor that at
humid
other times we say it is more ________.
The
amount of water vapor that air can hold
temperature
depends on the air ___________.
The warmer
more water vapor the air
the temperature, the _____
can hold. The cooler the temperature, the
______
water vapor the air can hold.
less
___________
_________
is what
Relative
humidity
meteorologists refer to when reporting the
amount of ________
_________
in the air. At
water
vapor
100% humidity the air can not hold any
_______
more water vapor, and water returns to its
liquid
_________
form. The temperature at which
condenses is called a dew
water vapor ___________
point.
Why do you feel more comfortable on
a hot, dry day than on a hot, humid
day?
 On a hot dry day there is less humidity
and less water vapor in the air. High
levels of water vapor in the air (highly
saturated air) doesn’t have more room for
water to go into it and it feels sticky to
your skin.
Weather Game…
Temperature
Humidity
Density
Air Pressure
H
H
H
H
L
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L