Download Chapter 6 Study Guide

Chapter 6 Study Guide
The Water Cycle
Lesson 1 – What is the Water Cycle?
The Water Cycle
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Water is constantly moving through the environment
Water Cycle - Water moves from Earth’s surface to the air and then back to the surface of the
Earth again in a never ending process
o Energy from the sun is important to the Water Cycle
o When the sun’s energy warms up the water on Earth’s surface, the liquid changes from
a liquid to a gas, called water vapor, and rises into the air
o When the water vapor cools, the becomes liquid again and falls back to Earth in the
form of precipitation
o Precipitation – water that falls to Earth’s surface
 Many forms – rain, snow, sleet, hail
Parts of the Water Cycle
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Evaporation – the process of a liquid changing into a gas
o Water from lakes, rivers, and the ocean evaporate every day
o Water also evaporates from puddles, soil, and even your skin
Condensation – the process of a gas changing into a liquid
o Water vapor mixed with other gasses in the air
o When water vapor moves up in the air, it cools
o The water vapor and the air collect small dust particles, which form clouds
o Inside the cloud, droplets of water join together to make larger droplets
o When the droplets become too heavy, the fall to earth as precipitation
Groundwater and Runoff
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Some precipitation is soaked up by the soil, plants need the water and use most of it
Some precipitation evaporates as part of the water cycle
Some precipitation goes deeper into the ground
o This water moves down until it gets to solid rock and begins to collect there
o Groundwater – a collected body of water underground
Runoff – the remainder of the water that does not evaporate or get soaked into the soil
o This water flows into creeks and streams, which flow into rivers and other bodies of
water
Lesson 2 – How is the Water Cycle related to Weather?
Kinds of Precipitation
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Rain – most common, liquid water
Sleet – frozen rain, rain falls through a layer of freezing cold air
Snow – made of ice crystals, water vapor turns directly into ice
Hail – round pieces of ice, rain freezes then falls to a warmer part of air
o These pieces of frozen rain are carried back up by the wind and it freezes
o This happens over and over again
Severe Storms
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Thunderstorm – storms with lightning, strong winds, and heavy rain
Tornado – a fast spinning spiral of wind that stretched from cloud to the ground
o Sometimes can be formed during a thunderstorm
o Wind speeds greater than 250 miles per hour (400 km/hr)
o About 800-1,000 every year
Hurricane – a large tropical storm
o Wind speeds of 74 miles per hour (119 km/hr) or more
o Form over warm water in tropical areas, typically over the ocean
o Once they move over land, they no longer get energy from warm water and become
weaker
 Rain, waves, and flooding usually happen on land
o Eye – the center of the storm
Weather Safety
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Severe storms are dangerous
o Broken power lines and fallen trees
o Flooding
Ways to warn people
o Weather sirens, especially in areas that have tornadoes
o Listen to the radio or watch the news
Sometime people are asked to evacuate or to seek shelter in a storm cellar
Lesson 3 – How do Land Features affect the Water Cycle?
Sea Breezes and Land Breezes
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Land heats up and cools more quickly that water
Temperatures over land are always different from the temperatures over water
Sea Breeze
o During the day, air over water cooler than air over land
o Hot air over the beach is pushed upward by the cool air moving in from the water
Land Breeze
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During the night, air over land is cooler than air over water
A breeze moving from the land to the water
Sea Breeze Storms
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Sometimes cool sea breezes push clouds towards the shore, which produce storms over land
Peninsula – a piece of land that is surrounded by water on three sides (like Florida)
o Sea breezes can come in from both sides and collide over land, causing a sea breeze
storm to form
Rain Shadows
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Rain shadow – the are on the far side of a mountain that little to no rain
o Air is pushed up the side of the mountain and then over it
o As the air moves up, it cools and brings rain to that side of the mountain
o As the air moves to the other side of the mountain, the air is dry and it does not rain
Lesson 4 – How can Weather be Predicted?
Air Masses
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Air Mass – large body of air with similar temperature and moisture levels (amount of water in
the air)
Temperature and moisture levels depend on where the air mass was formed
o Formed over water – lots of moisture
o Cold air masses are in the northern part of the U.S.
o Warmer air masses are in the southern part of the U.S.
o Cold, wet air masses bring snow
o Cold, dry air masses bring cool weather with very little or no precipitation
o Warm, moist air masses usually bring precipitations
o Warm, dry air masses bring little to no precipitation
Warm air is lighter than cold air
o Warm air masses are pushed upward and the cold air masses sink
Fronts
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Front – the border between air masses come they come into contact with each other
o Cold Front – cold air mass moving under a warm air mass
 The warm air begins to cool, causing condensation
 The condensation forms clouds
 Rain may begin and thunderstorms often develop
o Warm Front – warm air moves over cold air
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 Generally move more slowly, bringing steady rain
Stationary Front – when two air masses along a front do not have enough energy to
move
 Cloudy weathers and usually wet
 Can leave many inches of snow or cause flooding
Weather Maps
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Tell you about what the weather will be like in an area
Use many symbols to show different types of weather
o Sun symbol – sunny in an area
o Cloud with rain symbol – raining in an area
o Warm front symbol – a red line with half circles along it
o Cold front symbol – a blue line with triangles along it
Shows temperatures (usually in Fahrenheit in the U.S.)
o Can be shown in colors instead of numbers: red means very hot, orange means warm,
yellow means mild, green means cold, and blue means very cold
Shows wind speed and direction, air pressure, high and low temperatures
Measuring Weather
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Thermometer – measures temperature
Barometer – measure air pressure
Anemometer – measures wind speed