Motion of the Earth
Climates, Seasons, & Days
What do you know?
In your groups round robin what you know
about the motion of the Earths & the effects
it has on us.
Earth’s Motion
• Earth has two major types of motion
• Earth’s Rotation
• Earth’s Revolution
How Earth Moves
• In your group & demonstrate the
difference between a Rotation & a
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 Rotating
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
Earth’s Revolution
Changing Seasons
If we are closer in January than in July, why is it that we have
are coldest days of the year during this time?
• 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
Seasons on Earth
• The height of the sun above the horizon
varies with the season.
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
Seasons on Earth
• Earth has seasons because it is tilted as it
revolves
around the sun.
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
Effects of Earth’s Revolution
Seasons at a Glance
Winter Begins
(solstice)
Spring Begins
(equinox)
Summer Begins
(Solstice)
Autumn Begins
(Equinox)
December 21st or 22nd
March 20th or 21st
June 21st or 22nd
September 22nd or 23rd
Animation
• Revolution
revolution
• Test your knowledge
• Extra Practice
• Click on view
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
Climatic Zones
Air Temperature by Month
World Temperature Zones
• Based on latitude, Earth’s surface can be
divided into a tropical zone, two temperate
zones, and two polar zones.
Biomes are large geographical areas
with similar climates and ecosystems