Rotation and Revolution of the Earth Aphelion and Perihelion Four Seasons Seasonal Changes Solstice and Equinoxes Standard Time Zones Land of the Midnight Sun

1. MOTIONS
of the Earth
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2. Basic Understandings
Rotation –
the Earth spins on an
imaginary line called
‘axis ‘ from east to west
direction.
“The Earth spins on its axis
once every 24 hours or 1
day.”
Major Motions of the Earth
Revolution –
movement around the
Sun in an elliptical orbit.
Complete r = 365 ¼ days.
Speed = 29.8 km/s
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3. The Earth is farthest from the Sun at
aphelion on July 3 or 4 at approx.
152.1 million kilometers.
The Earth is nearest from the Sun at
perihelion on January 3 or 4 at
approx. 147.2 million kilometers.
Basic Understandings
94,500,000 miles
93,000,000 miles
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4. EARTH'S
motion
around the
Sun, not as
simple as you
thought.
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5. The four important positions of the Earth
with respect to its revolution around the Sun.
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6. Seasonal Changes
-are caused by
the tilting of the
Earth and its
revolution
around the Sun.
These bring
about the
variations in
the lengths of
day and night.
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7. The Earth’s Tilted Axis
and Seasonal Changes
As the Earth rotates and
revolves around the Sun, its
axis tilts at an average of 23.5 °
from the vertical line.
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8. Seasonal Changes
When the longest
days and shortest
nights occur in
Northern Hemisphere.
Summer
Warm weather
-when the North Pole
Is directly tilted
toward the Sun.
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9. Seasonal Changes
-when the North
Pole is tilted away
from the Sun.
Winter
Cool weather
Earth will experience
the shortest day and
longest night of the
year.
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10. Seasonal Changes
Days and nights are
equal all over the
Earth.
Equinoxes
Equinox
- means equal
day and night.
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11. Seasonal Changes
It tells the time
when the Sun stops
its journey to the
north as it rises
everyday.
Solstice
Solstice
- means “Sun stops”.
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12. The midnight sun is a natural phenomenon that occurs in the summer months
in places north of the Arctic Circle or south of the Antarctic Circle, when the sun
remains visible at the local midnight.
Landof the
Midnight Sun
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14. The earth covers 360° in its
24-hour rotation. Thus, for
every hour of rotation it
covers 15 ° of longitude. This
is the basis for determining
time all over the globe.
Timeand
Standard Time Zones
Local Time -
If we would base time on the Earth’s
rotation, covering 360° in a day, or
15° in an hour, or one degree every
four minutes, each meridian would
have its own time.
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15. STANDARD TIME ZONES OF THE WORLD
The Earth was divided into 24 time zones, each zone one
hours apart, covering approximately 15° of longitude.

16. STANDARD TIME ZONES OF THE WORLD
Therefore, the different places of the world have different
times based on the meridian passing through them.

17. Not all countries,
however, follow the
standard time system.
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18. Australia
Standard Time System
- was adapted based on
the Greenwich Prime
Meridian (0°) as agreed
upon in an international
conference held in
Washington, D.C. in
1884.
Bigger countries
cover more than
one time zone.
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19. When one travels around the
world, crossing boundaries and
going from one hemisphere to
another, it is important to take
note of time differences as well as
the change in dates upon
crossing the
International Date Line.

20. Motions of the Earth
Revolution
Revolves around
the sun.
Takes about a year or
365 ¼ days.
Causes changes in
seasons.
Follows an elliptical
orbit.
Rotation
Rotates on its axis.
Rotates for a period
of 24 hours.
Causes night and
day.
Rotates in an
eastward direction.
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21. North Pole is directly tilted
toward the Sun.
It occurs every June 21 or 22.
Longest day and shortest night
are experienced.
Vertical rays of the Sun strike
the Tropic of Cancer.
Seasons and the Positions of the Earth around the Sun
with reference to the Northern Hemisphere
Summer solstice
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22. No pole is tilted toward the
Sun.
It occurs every September 22
or 23.
Equal length of day and night
is experienced.
Vertical rays of the Sun strike
along the Equator.
Seasons and the Positions of the Earth around the Sun
with reference to the Northern Hemisphere
Autumnal equinox
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23. South pole is directly tilted
toward the Sun.
It occurs every December 21
or 22.
Shortest day and longest night
are experienced.
Vertical rays of the Sun strike
the Tropic of Capricorn.
Seasons and the Positions of the Earth around the Sun
with reference to the Northern Hemisphere
Winter solstice
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24. No pole is tilted toward the
Sun.
It occurs every March 21 or
22.
Equal length of day and night
is experienced.
Vertical rays of the Sun strike
along the equator.
Seasons and the Positions of the Earth around the Sun
with reference to the Northern Hemisphere
Spring equinox
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25. Mechanism of the Seasons
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