Transcript Getting to Know Earth

Planet Earth
Getting to Know Earth
•The atmosphere, hydrosphere, and lithosphere form the
biosphere, the part of Earth that supports life for all
people, animals, and plants.
•Atmosphere is a thin layer of gases that surround
Earth and contains the air we breathe.
•Hydrosphere includes the liquid and frozen surface
water, groundwater, and water vapor in and around
oceans, lakes, and rivers on Earth.
•Lithosphere is the land or surface areas on Earth,
including the continents, islands, and ocean basins.
Planet Earth
Getting to Know Earth
•The atmosphere, hydrosphere, and lithosphere form the
biosphere, the part of Earth that supports life for all
people, animals, and plants.
•Atmosphere is a thin layer of gases that surround
Earth and contains the air we breathe.
•Hydrosphere includes the liquid and frozen surface
water, groundwater, and water vapor in and around
oceans, lakes, and rivers on Earth.
•Lithosphere is the land or surface areas on Earth,
including the continents, islands, and ocean basins.
Planet Earth
Getting to Know Earth
•The atmosphere, hydrosphere, and lithosphere form the
biosphere, the part of Earth that supports life for all
people, animals, and plants.
•Atmosphere is a thin layer of gases that surround
Earth and contains the air we breathe.
•Hydrosphere includes the liquid and frozen surface
water, groundwater, and water vapor in and around
oceans, lakes, and rivers on Earth.
•Lithosphere is the land or surface areas on Earth,
including the continents, islands, and ocean basins.
Forces of Change
Earth’s Structure
•For millions of years, the surface of the Earth has
been moving.
•The Earth is composed of three layers—the core at
Earth’s center, the mantle layer of dense rock on the
outer core, and the crust forming Earth’s surface.
•Many scientists believe Earth was once a single land
mass called Pangaea, but then continental drift
slowly spread the continents apart.
•Plate tectonics describes the activities of continental
drift and magma flow; referring to the physical
processes that create and shape continents, islands,
oceans, and mountain ranges.
Forces of Change
Internal Forces of Change
•Mountains are formed when Earth’s giant continental
and oceanic plates collide.
•Moving plates sometimes cause Earth’s surface to
buckle forming folds; in other cases the moving plates
form cracks called faults.
•Violent movements of Earth’s crust along fault lines are
called earthquakes, which dramatically change the
surface of the land and the floor of the ocean.
•Volcanoes are mountains formed by lava or magma that
breaks Earth’s surface.
Forces of Change
External Forces of Change
• Wind and water break down the Earth’s surface
through weathering and erosion.
•
Physical weathering happens when large masses of
rock are broken down into smaller pieces.
•
Glaciers are large bodies of ice that move across the
Earth’s surface, changing the landscape as they flow.
•
Soil building takes thousands of years of weathering,
erosion, and biological activity and is influenced by
five factors; climate, topography, geology, biology,
and time.
Earth-Sun Relationships
Climate and Weather
•Weather is the condition of the atmosphere at a
specific time.
•Climate refers to the average weather conditions
over many years.
•Earth’s tilt on its axis in relation to the sun affects
temperatures from day to night.
•The rotation of Earth around the sun takes one year;
this revolution affects temperatures from season to
season.
Earth-Sun Relationships
The Greenhouse Effect
•The greenhouse effect allows trapped
atmospheric gases to radiate heat that warms the
Earth.
•Under normal conditions, the atmosphere
naturally provides enough insulation to promote
life on Earth.
•The radiation the Earth receives from the sun
must equally balance with the heat radiated back
into space to avoid temperature extremes in order
to support life.