CHAPTER 24 Study Guide

24.1 The Atmosphere

Key Concepts

• Earth's atmosphere forms a protective boundary and provides conditions that are suitable for life.

• Earth's atmosphere is a mixture of many gases in which tiny solid and liquid particles are suspended.

• As altitude increases, pressure and density decrease.

• Scientists use variations in temperature to divide the atmosphere into four vertical layers.

Vocabulary atmosphere, air pressure, barometer, troposphere, weather, stratosphere, ozone layer, mesosphere, thermosphere, ionosphere, aurora

24.2 The Sun and the Seasons

Key Concepts

• Earth moves by rotation and revolution.

• Scientists use lines of latitude to mark out regions within which temperatures are similar.

• The seasons are caused by the tilt of Earth's axis.

Vocabulary rotation, revolution, tropic zone, temperate zones, polar zones, solstice, equinox

24.3 Solar Energy and Winds

Key Concepts

• Solar energy may be reflected, absorbed by the atmosphere, or absorbed by the surface.

• Energy is transferred within the troposphere in three ways: radiation, convection, and conduction.

• Winds are caused by differences in air pressure.

• Sea breezes and land breezes are local winds. Trade winds and westerlies are global winds.

Vocabulary greenhouse effect, wind, local wind, sea breeze, land breeze, global winds, Coriolis effect, monsoon, jet stream

24.4 Water in the Atmosphere

Key Concepts

• Water vapor condenses as dew, frost, clouds, or fog.

• Clouds form as warm, moist air rises and water vapor condenses in the atmosphere. The basic cloud forms are stratus, cumulus, and cirrus.

• The most common types of precipitation are rain, snow, hail, sleet, and freezing rain.

Vocabulary humidity, relative humidity, dew point, cloud, fog, stratus clouds, cumulus clouds, cirrus clouds

24.5 Weather Patterns

Key Concepts

• An air mass forms when a large body of air becomes fairly stationary over Earth's surface or as air moves over a large uniform area.

• There are four types of fronts: cold fronts, warm fronts, stationary fronts, and occluded fronts.

• Cyclones are associated with stormy weather. Anticyclones are associated with clear, calm weather.

• Thunderstorms form when columns of air rise within a cumulonimbus cloud. A tornado forms when an area of rotating air develops in a thunderstorm.

Vocabulary air mass, front, cold front, warm front, stationary front, occluded front, cyclone, anticyclone, thunderstorm, lightning, thunder, tornado, hurricane

24.6 Predicting the Weather

Key Concepts

• Meteorologists use technologies such as Doppler radar to help predict the weather.

• Weather maps often show predicted temperatures, cloud cover, and precipitation.

Vocabulary meteorologists, isotherm, isobar

24.7 Climate

Key Concepts

• Climate is a pattern of weather over many years.

• The two main factors that determine a region's climate are temperature and precipitation.

• Factors that affect a region's temperature include its latitude, distance from large bodies of water, ocean currents, and altitude.

• Factors that affect a region's precipitation include its latitude, the distribution of air pressure systems and global winds, and the existence of a mountain barrier.

• Scientists study past climates by analyzing data from ice cores, fossils, the pollen record, and tree rings.

• Natural causes of climate change include plate tectonics, variations in Earth's position relative to the sun, and variations in solar radiation, ocean circulation, and volcanic activity.

• Many human activities are increasing the levels of greenhouse gases in the atmosphere. This increase is causing global temperatures to rise.

Vocabulary climate, desert, ice ages, El Niño, global warming

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