Download Chapter 2 Section 1

Chapter 2 Section 1
The Water Planet
Water Cycle
• As we already know, our planet is
70% water
• As a liquid, Water is in the lakes,
streams, rivers, and oceans but it is
also in the air around us in the form
of _______________
• _______________ - water in the
form of a gas
• Glaciers also hold earths water as a
solid.
• Even the human body is about 60%
water.
The Water Cycle
What three forms does
water on earth come in?
• Liquid – rivers, streams, lakes, and
oceans
• Gas – water vapor
• Solid - glaciers
Water Cycle
• The amount of water on the earth’s
surface does NOT change.
• It does however move around in the
____________________.
• The water cycle moves the earth’s
water from the oceans and other
bodies of water, to the air, and then
back down to the oceans again.
Evaporation
Evaporation – the sun’s heat turns
liquid into a gas
This gas is known as
__________________
Another word for water vapor is
____________________
Temperature determines how much
water vapor the air can hold.
Evaporation
Critical Thinking Question
• What kinds of temperatures
can hold more water vapor,
cold or hot?
Answer
• HOT
• Warmer temperatures can hold more
humidity. This is why we have sticky,
hot days in the summer. The sun
rays are stronger and the
temperature is warmer perfect for
evaporation and humidity.
Condensation
The warm evaporated air rises as it
rises, it also cools
As the water vapor cools, it turns
back into a liquid
This process of water vapor cooling
and then turning back into a liquid is
called
CONDENSATION.
Condensation
• Condensation forms clouds.
• As the water vapor turns back into a
liquid, during condensation, it forms
tiny droplets of water. This water
combines to form clouds.
Condensation
Precipitation
• These tiny droplets of water will fall back
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•
•
•
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to the earth’s surface in the process
known as Precipitation.
The water can fall back to the earth’s
surface as:
Rain
Snow
Sleet – frozen rain that makes an icy
coating, usually comes in winter
Hail – frozen rain – usually comes in
spring, summer
Precipitation
Collection ( run-off)
• As the precipitation hits the earth’s
surface it will then soak back into the
ground in a process known as
collection.
• Rivers, and streams then carry the
water that soaked into the ground
back to the oceans and the cycle starts
over again.
Collection
Question
• What are the 4 steps to the
water cycle?
Answer
• Evaporation
• Precipitation
• Condensation
• Collection
Water Resources
• Tell me how many different
ways you use water every
day?
Critical Thinking Questions
• If the earth is made up of
70% water, then why is there
so much concern over the
shortage in water?
Answer
• It is true the earth is more than 70%
water which has earned it its name of
the BLUE PLANET.
• However only 2% of the earth’s
water is freshwater.
• Most of that 2% of water is frozen in
polar ice caps and glaciers. (about
80% of the 2 %)
• Only a very small fraction of
freshwater is found in lakes and
rivers.
Freshwater
• We also get freshwater from
________________
• Groundwater is water that fills
tiny cracks and holes in the rock
layers below the surface of the
earth.
• There is 10X more groundwater
than there is water in lakes and
rivers.
How Do We Get
Freshwater?
• We get freshwater from wells
• Aquifiers – underground rock layers
that water flows through.
Salt Water
• Almost 98 % of earth’s water is salt
water
• The Oceans consist of salt water.
• The Pacific Ocean is the largest ocean
– it is larger than all of the land area
on earth combined.
• Bodies of water smaller than oceans
are called SEAS, GULFS, BAYS,
STRAITS