Chapter 4 – Chapter 4 – Earth’s WaterEarth’s Water

Lesson 2 –Lesson 2 –The Water CycleThe Water Cycle

© Brent Coley 2009 | www.mrcoley.com© Brent Coley 2009 | www.mrcoley.com

What makes water change What makes water change form?form?• Water can be in three forms, Water can be in three forms, or states: or states:• solidsolid - ice - ice• liquidliquid - water in a glass or - water in a glass or lakelake• gas (water vapor)gas (water vapor) - - invisibleinvisible gas in the air or steam gas in the air or steam

What makes water change What makes water change form?form?• evaporationevaporation: liquid changing : liquid changing toto gas when it heats up gas when it heats up

• condensationcondensation: gas changing : gas changing toto liquid when it cools down liquid when it cools down

What makes water change What makes water change form?form?• meltingmelting: solid changing to: solid changing to liquid when it heats up liquid when it heats up

• freezingfreezing: liquid changing to: liquid changing to solid when it cools down solid when it cools down

solid + heat = liquid + heat = solid + heat = liquid + heat = gas gas

gas - heat = liquid - heat = gas - heat = liquid - heat = solidsolid

meltingmelting evaporatioevaporationn

condensatiocondensationn

freezingfreezing

What happens to water What happens to water after it evaporates?after it evaporates?• Evaporated water goes up Evaporated water goes up intointo the air and is moved by wind the air and is moved by wind (moving air). (moving air).

• Air is made of particles of Air is made of particles of gasesgases like oxygen. like oxygen.

What happens to water What happens to water after it evaporates?after it evaporates?• warm air:warm air:• less particlesless particles• particles move fasterparticles move faster and spread out and spread out

• cold air:cold air:• more particlesmore particles• particles closerparticles closer together together

warm airwarm air

cold aircold air

What happens to water What happens to water after it evaporates?after it evaporates?• WarmWarm air air risesrises..

• ColdCold air, because it has more air, because it has more particles, is heavier and particles, is heavier and sinkssinks..

What happens to water What happens to water after it evaporates?after it evaporates?• Sea breezeSea breeze::• Land heats up during the Land heats up during the day.day.• Air above the land gets Air above the land gets warmerwarmer and rises. and rises.• Air over water sinks and Air over water sinks and blowsblows toward land to replace toward land to replace risingrising warm air. warm air.• Moves from Moves from water to landwater to land..

What happens to water What happens to water after it evaporates?after it evaporates?• Land breezeLand breeze::• At night, land cools off At night, land cools off fasterfaster than water. than water.• Air stays warmer longer Air stays warmer longer overover water, so it rises. water, so it rises.• Air over land sinks and Air over land sinks and blowsblows toward water. toward water.• Moves from Moves from land to waterland to water..

How do clouds form?How do clouds form?• When liquid water When liquid water evaporates, itevaporates, it becomes water vapor and becomes water vapor and rises.rises.• As water vapor rises, it coolsAs water vapor rises, it cools down & turns back to tiny down & turns back to tiny liquidliquid water droplets water droplets (condensation).(condensation).• When more and more waterWhen more and more water droplets collect, a cloud is droplets collect, a cloud is formed. formed.

How do clouds form?How do clouds form?• Cirrus cloudsCirrus clouds::• Form high in the skyForm high in the sky• Are thin and wispyAre thin and wispy

How do clouds form?How do clouds form?• Cumulus cloudsCumulus clouds::• Puffy and whitePuffy and white

How do clouds form?How do clouds form?• Stratus cloudsStratus clouds::• Low-flying cloudsLow-flying clouds• Spread like a blanket Spread like a blanket acrossacross the sky the sky

Will it rain?Will it rain?• PrecipitationPrecipitation: water that : water that fallsfalls from the air. from the air.• It comes in four forms:It comes in four forms:• RainRain• SleetSleet• HailHail• SnowSnow

Will it rain?Will it rain?• RainRain::• Liquid drops of water Liquid drops of water that fall when the that fall when the temperature is above temperature is above 32° F (freezing point 32° F (freezing point of water). of water).

Will it rain?Will it rain?• SleetSleet::• Mixture of rain and snowMixture of rain and snow

Will it rain?Will it rain?• HailHail::• Frozen rain dropsFrozen rain drops• Forms in layers – wind Forms in layers – wind keepskeeps pushing hailstone back up pushing hailstone back up until it gets large enough until it gets large enough toto fall fall

Will it rain?Will it rain?• SnowSnow::• Water vapor turns directly Water vapor turns directly intointo solid flakes (crystals). solid flakes (crystals).• Occurs when temperature Occurs when temperature is is below 32° F. below 32° F.

The Water CycleThe Water Cycle

EvaporatioEvaporationn

CondensatioCondensationn

PrecipitatioPrecipitationn

Water bottle, hail, and cloud Water bottle, hail, and cloud images courtesy of Wikimedia images courtesy of Wikimedia Commons and used under a Commons and used under a

Creative Commons Creative Commons Attribution license. All other Attribution license. All other images courtesy of Microsoft images courtesy of Microsoft

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