Chapter 2

Planet Earth

Solar Energy

• Energy from the sun.– Need for survival.– Amount of energy

received, changes.

• Why?

Rotation

• One complete spin of the earth.– Takes 24 hours.

• Rises in the east, sets in the west.

• The sun does not move.

Revolution

• Earth spins on its axis.• While earth revolves

around the sun.• Takes 365.25 days for a

complete revolution.• Calendar year.• Leap year?

Tilt

• Earth is tilted 23.5 degrees.

• Seasons?

Equator

• Line across center of earth. That divides the world north and south.

Latitude

• The distance north and south of Earth’s equator.

Prime Meridian

• Line of Longitude at 0 degrees.

Longitude

• The distance east and west of Earth’s prime meridian.

The Seasons

• Many places on earth experience four seasons.

• Winter, Summer, Fall, and Spring.

• Seasons are based on temperature, and length of days.

• Some seasons are based on rain fall.

Winter and Summer

• Changes in seasons are based on the earth’s tilt.

• During winter the earth is tilted away from the sun.

• During summer earth is tilted toward the sun.• The northern and southern hemispheres

experience opposite seasons.

Spring and Fall

• First day of spring and fall, the earth does not tilt toward the sun.

Rainfall and Seasons

• Some areas in the world mark their seasons by rainfall.

• Tropics are regions close to the equator.• Winds will either bring dry or wet air to the

region. • Seasons become known as wet or dry.

Salt Water

• 97% of earths water is salt water.

• Water covers 71% of earth.

Freshwater

• 3% of our water supply.• Water used to sustain

life.• Most of the fresh water

are in glaciers.• Surface water is found in

streams, rivers, and lakes.• Less than 1 percent

comes from surface water.

continued

• Groundwater is found under earth’s surface.

Precipitation

• Water that falls to earth’s surface.

• Rain, snow, sleet, or hail.

Water Cycle

• Water cycle is the movement of water from Earth’s surface to the atmosphere and back.

Earth’s plates

• Solid inner core, mantle, and crust. – Three layers of earth.

• Earth’s continents are apart of earth’s crust.

• Plate tectonics- Slow moving plates, or pieces of earth’s crust.

Continued

• Ocean plates• Continental plates• What do they mean?

Plate Tectonics

• Earth’s surface is divided into a dozen or so slow-moving plates.

• Pieces of earth’s crust.• Plates move up to

several inches per year.• Continental Drift

Plates Collide

• Ocean Trenches are formed when two ocean plates collide, and one of them goes under the other one.

• When an ocean plate and continental plate collide it results in mountain building.

Plates Separate

• When plates move apart, gaps allow magma to rise.

• Lava-Magma that reaches the earth’s surface.

Plates Slide

• Earthquakes-are sudden, violent movements of Earth’s crust.

• Take place along earth’s faults.– Breaks in the crust

Ring of Fire

• Region around the Pacific Plate.

• Produces violent earthquakes and volcanic eruption along the edges.

Weathering

• Process by which rock is broken down into smaller pieces.

Erosion

• Movement of sediment from one location to another.