Transcript Earth Science - Wiki-by

Science Lesson
Ashley Smith
Earth Materials
• Earth materials are solid rocks and soils,
water, and the gases of the atmosphere. The
varied materials have different physical and
chemical properties, which make them useful
in different ways, for example, as building
materials, (e.g., stone, clay, marble), as
sources of fuel, (e.g., petroleum, natural gas)
or for growing the plants we use as food.
Earth materials provide many of the
resources that humans use.
Rocks
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Rocks have different physical properties.
Rocks are useful to human beings in many ways.
Many rocks are composed of smaller parts called minerals.
Rocks have some characteristics that can’t be seen, but can be
“tested” for.
• Earth materials change over time, usually due to slow
changes.
• Changes in rocks is called weathering, and it can be caused by
wind, water, or anything that causes small pieces of rock to
break off from larger rocks.
Rocks Continued
• There are three types of rocks---igneous,
sedimentary, and metamorphic.
• Igneous rocks form from melted rock that has
cooled and hardened.
• Sedimentary rocks form from layer of sediment.
• Metamorphic rocks have been changed by heat
and pressure.
• The Earth is a ball of rock with three layers--crust, mantle, and core. (3-30 miles thick).
Soil
• Soils have properties of color and texture,
capacity to retain water, and ability to support
the growth of many kinds of plants, including
those in our food supply.
• Soils are made up of smaller parts, including both
minerals (from weathered rocks), and plant and
animal remains.
• Soils also contain air and water.
• One variable property of soil is “water-holding
capacity,” a property that is important for
plant growth and some other functions of soil.
Soil Continued
• Soil is an important resource that can be
harmed.
• There are several ways to conserve soil---strip
cropping, contour plowing, no-till farming,
and planting trees
Water
• Water is one of the most important substances on Earth.
More than two-thirds of Earth’s surface is covered by
water.
• All people need fresh water, but most of Earth’s water is
not fresh.
• Most of the water on Earth is salt water.
• Estuaries are places where fresh water from a river mixes
with salt water from the ocean.
• Water can exist in three different forms in nature---liquid
(water), solid (ice), gas (water vapor).
• The water cycle is the movement of water from Earth’s
surface into the air and back to the surface again.
The Water Cycle
Processes That Change the Earth’s
Surface
• Earth’s surface has many types of landforms--mountains, valleys, canyons, plains, plateaus, and
barrier islands.
• Weathering breaks down rocks in several ways.
• Erosion moves pieces of rock around in many
ways.
• The movement of glaciers, wind, and water can
change the land.
• Earthquakes and volcanoes cause rapid changes
to the land.
Earthquakes
• An earthquake is a sudden, rapid shaking of
the earth caused by a release of energy stored
in rocks. Earthquakes are a natural
phenomenon. They are happening all the time
but are often not even noticed by people until
they cause visible damage.
• We see the results of earthquakes in
landslides, tsunamis, faults and rifts.
Volcanoes
• Volcanoes also can occur as a result of plate movement. A
volcano is a vent in the surface of the Earth through which
magma (molten rock called “lava” when it reaches the
surface) and associated gases, erupt.
• Materials ejected from the vent could include:
• cinder—dark colored pieces of rock thrown from a volcano
• pumice—bubbly, frothy rock that is hardened
• ash—fine grained particles less than 2 mm across
• Volcanoes also trigger
• mudflows, avalanches, and cracks or fissures in the Earth’s
surface.
Landslides
• A landslide is a mass of rocks, soil and debris
that suddenly slides down a slope. A landslide
can be caused by rocks breaking from an
outcrop and tumbling down a cliff, heavy rains
soaking the ground causing mud to flow down
a hillside, or an earthquake shaking the
ground causing it to move down a steep slope.
Atmospheric Gases
• The atmosphere of Earth is a layer of gases
surrounding the planet Earth that is retained
by Earth’s gravity.
• The atmosphere protects life on Earth by
absorbing ultraviolet solar radiation.
• The atmosphere is…..78% Nitrogen, and 21%
Oxygen. There are small amounts of argon,
carbon dioxide and water vapor too.