Download Storms Lessons 4

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Catastrophic Events Storms Lesson 4-7 Study Guide
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Storms Lessons 4-7 Study Guide
Lesson 4 - Air Masses
 The air above a cold surface will be cold.
 The air above a warm surface will be warm.
cool
air
warm
air
Cold air sinks because
it is more dense.
Warm air rises because
it is less dense.
cold
hot
Lesson 5 - Convection Currents
warm
air or
water
cool
air or
water
 caused by a difference in temperature (uneven
heating)
 can happen in liquids and gasses
o less dense warm air rises above the candle
o more dense cold air sinks around the ice water
o cold air replaces the warm air that rose
(higher pressure always moves to lower pressure)
sea breeze
land breeze
day - wind from cooler sea to land
night - wind from cooler land to sea
1
Tornado Alley:





cold dry air from Canada & Rocky
Mountains meets warm moist air
from Gulf of Mexico
dry air mass from land
moist air mass from water
front forms along boundary &
severe weather results
flat central plains don’t change
air masses
Weather Symbols:
high pressure - clear skies
H
low pressure -cloudy/stormy weather
L
cold front - colder temperatures and quick changes in weather
warm front - warmer temperatures and precipitation lasts for days
stationary front – air masses can’t move each other
Lesson 6 – Cloud Formation & Wind
3. precipitation
Water
Cycle
2. condensation
1. evaporation
1. evaporation – water heats and changes from a liquid to a gas
2. condensation – as the temperature cools (you go higher in elevation), the colder air can’t
hold as much water vapor. Water vapor changes from a gas to a liquid and clouds form
(water droplets condense on dust particles) under low pressure.
3. precipitation - water droplets collect and get too heavy (rain, snow, etc. falls to ground)
60°
30º
polar easterlies (E → W)
Global Winds
westerlies (W → E) move the weather across the US
trade winds (E → W) northern hemisphere
0º
trade winds (E → W) southern hemisphere
2
Uneven heating of Earth’s surfaces creates convection currents that move air creating wind.
Lesson 7 – Ocean Currents
 wind creates surface currents
 deep ocean currents are convection currents caused by uneven heating of ocean water
o warmer temperatures at equator – currents move towards cooler poles
o cooler temperatures at poles – currents move towards equator
 ocean currents affect climate
o warm ocean currents warm nearby land
 Gulf Stream warms eastern US & western Europe
o cool ocean currents cool nearby land (California)
Gulf Stream
3