Earth rotates on its axis once every 24 hours, causing day and night. It also revolves around the sun once every 365.25 days, causing seasons. Earth's axis is tilted at an angle of 66.5 degrees, which causes the length of days and nights to vary throughout the year and creates different seasons in each hemisphere simultaneously. The moon's gravitational pull causes high and low ocean tides daily as well as solar and lunar eclipses periodically as the moon passes between the earth and sun or earth passes between the moon and sun.

1. Earth Movement

2. Axis of Earth
• What is Axis?
Earth's axis is the
imaginary line which
goes through the north
and south poles and
around which Earth
spins.

3. • Think of Earth as a Giant
Spin top

4. Tilted Axis
• Earth axis is Tilted/Inclined at an angle of
66.5 degrees to the plane of its orbit.
Angle from Plane
is 66.5 Degree

6. Earth’s Hemispheres

7. NORTHERN
HEMISPHERE
SOUTHERN
HEMISPHERE

8. EARTH MOVEMENT
• Earth is in a constant motion and performs
two different movements:
• Rotation around it’s
Axis.
• Revolution around
Sun

10. Rotation of Earth
• Causes Day & Night
• It takes approx. 24 Hours
for earth to complete
one rotation around
it’s Axis.
• The side of Earth facing
Sun has Day while the
side away has Night.

13. • Earth rotation is anti-clockwise
• Because of which:
- Sunrises in the east
- Sun travels across
the sky
- Sunsets in the west

14. Effects of Tilt
• Difference in the Length
of Day & Night.
• Different
Seasons
at same
time.

15. Revolution of Earth
• Revolution is the movement of one object
around another object.
• Earth is revolving around Sun and
completes one Revolution In 365 Days
and 6 Hours

16. • Solar year = 365 and ¼ days
• Calendar = 365 days
• Difference = ¼ days or 6 hours in a year
¼ + ¼ + ¼ + ¼ = 1 day

17. Leap Year
• To compensate for every extra 6 Hours, a
day is added to the calendar after every
four years as 29th February:
Leap Year = Last two Figure of Desired
Year
4
• If answer has no remainder it is a leap year.

18. Leap Year or not?
• 1934
Not a leap year
• 1956
Leap year
• 1978
Not a leap year
• 1994
Not a leap year

19. Seasons
• This revolution of Earth is constant along
with the Axial Tilt which gives us different
seasons
• As Earth revolves, at different places the
seasons
occur.

21. Spring Equinox
Winter Solstice
Summer
Solstice
Autumnal
Equinox

22. Summer
Solstice
Winter
Solstice

23. • At Equinox March 21st & September 23rd
all places have equal Day and Night.

24. Moon

25. High / Low Tides
• As Earth & Moon attract each other toward
themselves like two magnets.
• The moon tries to pull at anything on the Earth to
bring it closer.
• But, the Earth is able to hold onto everything
except the water. Because it is constantly
moving and that allows moon to attract it

26. • This gravitation results in high and low
tides each day. And Ocean moves from
high tide to low tide and vice versa.

27. • As the moon travels around the earth and
as they, together, travel around the sun,
the combined gravitational forces cause
the world's oceans to rise and fall.

28. Eclipse
• Definition
– An obscuring of the light from one celestial
body by the passage of another between it

29. • There are two kinds of Eclipse but both
occur as a result of relative positions of
earth moon and sun
- Solar Eclipse
- Lunar Eclipse

30. Solar Eclipse
• When Moon comes between Sun & Earth.

31. • An eclipse of the sun occurs when the
moon revolving in its orbit around the
earth comes between the sun and the
earth. The moon blocks the light of the
sun and a shadow of the moon is cast
over the earth's surface.

32. Types of Solar Eclipse
• There are two types of solar eclipse:
– Total solar eclipse
– Annular solar eclipse
– Partial solar eclipse

33. • Total Solar Eclipse
– When the moon completely obscures the sun
• Annular Solar Eclipse
– When the Sun and Moon are exactly in line, but the
apparent size of the Moon is smaller than that of the
Sun. Hence the Sun appears as a very bright ring
surrounding the outline of the Moon
• Partial Solar Eclipse
– When the Sun and Moon are not exactly in line and
the Moon only partially obscures the Sun

34. Solar Eclipses in 2012
Type
Date
Region
Annular
May 20
China, Japan, Pacific,
West U.S.
Total
Nov 13
North Australia, South
Pacific

35. Lunar Eclipse
• When Earth comes between Sun and
Moon

36. • A lunar eclipse is when the Earth comes
between the Sun and the Moon causing a
shadow of Earth on the Moon.

37. Can be viewed with naked eye

38. Types of Lunar Eclipse
• There are two types of solar eclipse:
– Total lunar eclipse
– Partial lunar eclipse

39. • Total Lunar Eclipse
– When the Moon travels completely into the
Earth’s umbra
• Partial Lunar Eclipse
– When only a portion of the Moon enters the
umbra

40. Lunar Eclipses in 2012
Type
Partial
Date
Jun 04
Region
Asia, Aus., Pacific,
Americas