Chapter 2 Study Guide
****KNOW ALL VOCABULARY! ****
Energy in the Atmosphere Most of the energy from the sun reaches Earth in the form of visible light and infrared radiation,
and a small amount of ultraviolet radiation.
 When earth’s surface is heated, it radiates some of the energy back into the atmosphere as infrared
radiation.
 Clouds, dust and gases in the atmosphere reflect and scatter light
 The sky is blue because scattered light is blue.
Heat Transfer Heat is transferred in three ways: radiation, convection, and conduction.
 Give examples of each type of heat transfer.
 Temperature is measured by a thermometer. Mercury or colored alcohol heats up, expands, and rises
up the column. If it cools, it contracts and goes down the column.
 How do these three work together to heat the troposphere?
o Only some air near the Earth’s surface is warmed by radiation and conduction of heat from
the surface to the air. Convection causes most of the heating of the troposphere
Winds All winds are caused by differences in air pressure.
 Wind speed is measured by an anemometer, wind direction is measured with a wind vane.
 The wind-chill factor causes increased cooling because of the wind (making temperature feel
colder than it really is)
 Local winds are caused by unequal heating of Earth’s surface within a small area.
 The movement of air between the equator and the poles produces global winds.
 The major global wind belts are the trade winds, the prevailing westerlies, and the polar easterlies.
 Two calm areas where there is little to no wind are: doldrums (at the equator) and the Horse
latitudes (30º N and 30º S latitudes)
 Winds are named for the direction they blow from
Water in the Atmosphere Know the Water Cycle (p.61 text)
 Cold air can hold less moisture than warm air
 Clouds of all kinds form when water vapor in the air becomes liquid water or ice crystals (coolscondenses)
 Fog is a type of cloud that forms at or near the ground when the ground is cooler than the air
 Clouds are formed whenever air is cooled to its dew point and particles are present
 Meteorologists classify clouds into 3 main types
1. Cumulus
 Clouds that form less than 2km above the ground
 Fluffy, rounded piles of cotton
 Indicate fair weather
 Cumulonimbus clouds produce thunderstorms
 Cirrocumulus clouds look like rows of cotton balls and indicate that storms
are on the way
2. Stratus
 Form in flat layers
 “Strato” means spread out
 Usually cover all or most of the sky
 When thickened they may produce drizzle, rain, or snow and are then called
nimbostratus clouds
3. Cirrus
 Wispy, feathery clouds with feathery hooked ends
 Form at high levels (6km or higher) and at low temperatures
 Made of ice crystals
Precipitation Meteorologists measure rain with a rain gauge
 Common types of precipitation include rain, sleet, freezing rain, hail and snow
1. Rain
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2. Sleet
Most common form of precipitation
Drops of water at least .5mm in diameter
Mist/drizzle (smaller drops)
Fall from nimbostratus clouds
 Forms when rain drops fall through a layer of air 0 degrees C or colder and
freeze into solid particles
 Become solid particle of ice
 Smaller than 5mm in diameter
3. Freezing Rain
 Raindrops that freeze when they touch a cold surface
 Forms a glaze on surfaces
 Glaze: smooth, thick layer of ice built up on surface
4. Hail
 Round pellets of ice larger than 5 mm in diameter
 Only from in cumulonimbus clouds
 How do they form?
 Starts as an ice pellet
 Strong winds (updraft) cause pellets to rise up through cold layers
of air
 as moisture is added, it freezes, adding another layer of ice
 eventually the hailstone becomes too heavy and falls to the ground
 Hail stone can become very large and cause a lot of damage
5. Snow
 Water vapor converted directly into ice crystals (snowflakes)
 Snowflakes have endless patterns
 6 sides
Essay Topics:
1. Explain the difference between a land breeze and sea breeze.
2. Explain how clouds form.
3. Explain why warm air rises and cool air sinks.
4. List and describe the steps of the water cycle, starting with evaporation.