Motion of the Earth - Science With Ms. Hawkins



Motion of the Earth: Climates, Seasons, & Days

Earth has two major types of motion

Earth’s Rotation

Earth’s Revolution

Earth’s Rotation

The spinning of the Earth on its axis

the axis is the imaginary line that runs vertically through the center of the Earth

rotates from East to West

Rotation of the Earth produces 2 main effects:

Speed causes the length of a day to be about 24 hours

Causes daily changes from day to night

At all times half of the Earth faces the sun, while the other half is in darkness

Areas within the Artic & Antarctic circles experience several weeks of daylight or darkness depending on the time of year

Earth’s Revolution

The movement of Earth around the sun

Earth’s orbit is the slightly elliptical path that it travels around the sun

The sun is not in the center:

Around January 3rd earth is about 147million km away (closer)

Around July 4th earth is about 152 million km away (farther)

Revolution has 2 major effects:

The time it takes Earth to revolve around the sun once defines the length of a year

It takes 365 ¼ days to make one complete revolution

Every 4th year is leap year to make up for the extra day we gained

Earth revolves with a tilt of the axis

The revolution causes the changing seasons

Changing Seasons

Earth’s tilted axis combined with the revolution causes seasons to change

Earth’s axis is at an angle of 23.5° to its orbit

The axis always points in the same direction as the Earth orbits the Sun

The Northern hemisphere points toward the sun half of the year & away from the sun for half the year

The tilt causes the Earth’s surface to receive different amounts of solar energy throughout the year

Solstices

A solstice is the day when the Sun reaches its greatest distance north or south of the equator

The day Earth is tilted most toward the sun

June 21st is the summer solstice (northern hemisphere)

The most direct rays hit the Tropic of Cancer in the northern hemisphere causing the northern hemisphere to have warmer temperatures and more sunlight hours

Longest day of sunlight for the year

Daylight gets a little shorter each day after the solstice

Dec. 21st is the winter solstice (northern hemisphere)

The most direct rays hit the Tropic of Capricorn in the southern hemisphere causing the northern hemisphere to have cooler temperatures and less sunlight hours

Shortest day of sunlight for the year

Daylight hours get a little longer each day after the solstice

Equinox

An equinox is the day the Sun’s rays are directly above the Earth’s equator.

During this time equal amounts of sunlight are received all over the earth with the most direct rays hitting at 90° at the equator

March 21st is the spring equinox (northern hemisphere)

September 22nd is the autumn equinox (northern hemisphere)

Seasons are opposites in the Southern Hemisphere

Radiation from the Sun

The hemisphere that is tilted toward the sun receives more daylight hours and absorbs more radiation from the sun

The suns radiation strikes the earth surface at a higher angle when the hemisphere is tilted toward the sun

The higher the angle the more radiation the earth absorbs creating warmer temperatures

Climatic Zones

The amount of sunlight affects Climatic Zones

The latitude, distance north or south from the equator, affects the temperatures that commonly occur in that area.

The further from the equator the less direct the suns rays are

Theses yearly patterns cause weather patterns to occur in different regions of the earth that create climates

Biomes are large geographical areas with similar climates and ecosystems

[pic]

................
................

In order to avoid copyright disputes, this page is only a partial summary.

Google Online Preview   Download