Download 2.2 Land, Air, and Water

2.2 Land, Air, and Water
Geography
2.2 Land, Air, and Water
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Vocabulary
Landform
Mountain
Hill
Plateau
Plain
Plate tectonics
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Ring of fire
Pangaea
Plate
Weathering
Erosion
atmosphere
2.2 Land, Air, and Water
• Journal Entry
• Here’s your chance to be principal for a
day. Write the speech you will make to
your teachers outlining how they should
behave while you are boss.
• Start with:
– Today will be a good day for all of you who
follow the new rules…
2.2 Land, Air, and Water
• What is the Earth Made of?
– Continents are unique because of their
landforms (shapes and types of land)
– Mountains are landforms that rise usually
more than 2,000 feet above sea level. They
are wide at the bottom and rise steeply to a
narrow peak or ridge.
– Hills are lower and less steep than mountains,
with rounded tops.
2.2 Land, Air, and Water
– A plateau is a large, mostly flat area that rises
above the surrounding land. At least one
side of a plateau has a steep slope.
– Plains are large areas of flat or gently rolling
land. Many are along coasts. Others are in
the interiors of some continents.
2.2 Land, Air, and Water
• Pangaea—The Supercontinent
– For hundreds of years, as geographers
studied the Earth’s landforms, they asked
“where” and “why” questions. When they
looked at the globe, they thought they saw a
relationship between landforms that were very
far apart.
– Geographers theorize that millions of years
ago the Earth had only one huge landmass.
They called it Pangaea.
2.2 Land, Air, and Water
• Scientists reasoned that about 200
million years ago, some force made
Pangaea split into several pieces,
and it began to move apart. Over
millions of years the pieces formed
separate continents.
• (I would know everything in blue in order to
answer an essay question or two on the test).
2.2 Land, Air, and Water
• A theory called plate tectonics says
the outer skin of the Earth, called
the crust, is broken into huge
pieces called plates. The
continents and oceans are the top
of the crust. Below the plates is a
layer of rock called magma, which
is hot enough to be fairly soft. The
plates float on the magma, altering
the shape of the Earth’s surface.
2.2 Land, Air, and Water
• Volcanoes, Earthquakes, and shifting
plates.
– In some places, plates move apart, and
magma leaks out through cracks in the crust.
– In the oceans, over time, the cooling rock
builds p to form lines of underwater mountains
called ridges.
– On either side of the line, the plates move
away from each other.
2.2 Land, Air, and Water
• In other places, the plates push against
one another, forcing one plate under the
other. Tremendous pressure and heat
builds up. Molten rock races upward,
exploding onto the surface and producing
a volcano.
• Weathering is a process that breaks rocks
down into tiny pieces. Three things cause
weathering: wind, rain, and ice.
2.2 Land, Air, and Water
• Air and Water: Two ingredients for Life
– The Earth is surrounded by a thick layer of
special gases called the atmosphere. It
provides life-giving oxygen for people and
animals and life-giving carbon dioxide for
plants.
– The atmosphere also acts like a blanket. It
holds in the amount of heat from the sun that
makes life possible
2.2 Land, Air, and Water
• About 97 percent of the Earth’s water is
found in its oceans. This water is salty.
• Fresh water, or water without salt, makes
up only a tiny percentage of all the Earth’s
water.
• Most fresh water is frozen at the North and
South poles. People need fresh water for
many things. This fresh water comes from
lakes, river, and rain.
2.2 Land, Air, and Water
• Much fresh water, called groundwater, is
stored in the soil itself.
• Make sure that you have completed the
vocabulary.
• Make sure that you have completed the
journal entry.