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Earth’s Basics
• Earth is classified as a planet.
• It is a sphere • Its diameter is about
12,742 km across. • It is the fifth largest
planet in our solar system.
• Earth is the 3rd planet from the sun.
• Earth’s gravity keeps the moon in orbit.
Earth’s Axis
• Earth’s axis points to the North Star.
• An axis is an imaginary line that runs from the North Pole to the South Pole.
• The seasons are due to the tilt of Earth’s axis.
North Star
Earth’s Exterior
• About 70% of planet Earth is covered by water.
• The other 30% makes up the seven land continents made of rock.
• Earth’s crust (also called the lithosphere) is made up of two different plates that slide around on the mantle: oceanic plate & continental plate.
• Oceans, mountains, rivers, plains, marshes, glaciers, islands, beaches, valleys, peninsulas, canyons, volcanoes can be found on the crust.
• Earth’s crust is constantly changing due to the effects of weathering, erosion, deposition, the rock cycle, the water cycle, and the weather cycle.
Earth’s Atmosphere
• Earth is the only planet in the solar system that has an atmosphere that can sustain life.
• It protects us from the Sun’s heat and radiation and keeps our planet at a more moderate temperature.
• Our atmosphere contains these gases: – Nitrogen: 78%
– Oxygen: 21%
– Carbon Dioxide: .038%
• Earth’s atmosphere rises up about 10 miles away from the surface of the Earth.
Earth’s Interior
• Inner Core – Solid metal (iron and
nickel)
• Outer Core – Liquid metal (iron and
nickel)
• Mantle – Mostly melted rock – Convection currents
• Crust – Surface that we live
on – Solid rock
Day and Night
• The rotation of the Earth causes day and night.
• It takes 24 hours for Earth to make one turn on its axis.
Daytime Nighttime
Sunrise and Sunset • The apparent motion of the Sun is an illusion.
• Actually the Earth is turning to create this effect.
• The Sun rises in the East and sets in the West! (EW)
SUNRISE SUNSET