The document discusses the motion of the Earth and causes of day and night. It explains that the Earth rotates on its axis every 24 hours, which causes the apparent rising and setting of the Sun. This rotation also leads to day and night as different parts of the Earth face towards and away from the Sun at different times. The document further discusses how the Earth revolves around the Sun in 365 days, and how its tilted axis of 23.5 degrees, combined with its revolution, causes the seasons in the northern and southern hemispheres.

2. - We used to believe that the sun is moving as
it rises from the east & sets from the west.
-But the fact is the sun is not moving at all,
the earth is the one that is moving.

3. - The earth rotate “spins” around itself “its axis”
every day “24 hours”.
- And this rotation causes “the day & night” on
earth ,because as the earth is rotating around
itself, one side will be facing the sun so it will
have day, while the other side will be far from
the sun so it will have night .

4. - The Earth rotates around its axis “itself”
every 24 hours “day”.
- This rotation causes the “day & night” on
earth.
The Earth’s motion

5. “ When something appears to be moving”
The Apparent motion
Examples
-The sun appears to move , it
appears to rise from the east &
set to the west.
-The stars too appears to be
moving in the sky at night
Earth’s rotation causes apparent motion, but the sun and
stars are not moving in real/

6. Take a look at this picture
Have you ever
wonder what is
this dark area
standing beside
you?
It’s your shadow

7. - It’s the dark area that is formed
when the light is blocked by an
object.
What is the shadow?

8. But some times I saw my shadow
at different positions, How this
happens?
- This depends on the position of the sun,
as the earth move around its axis, the
position of the sun changes, that causes
the shadow to be found at different
positions.

9. Example
During the
early morning
Shadow is long
During the Mid
day
Shadow is short
During the
sunset
Shadow is long

10. - During the sun rise & the sunset:
The sun is at the sides of the tree, so a large
part of the tree blocks the sun light, so the
shadow is long.
-During the mid day:
The sun is above the tree, so only a
small part blocks
the sun light, so the shadow is short.

11. - The earth revolves around the sun.
- The earth completes one orbit around the
sun in 365 ¼ days.
The sun & the Earth
Revolution: When an object travels around another
object.
Orbit: It’s the path of the revolving object.
Earth
Orbit

12. - The axis of the earth is not straight.
- It’s titled to an angle of 23.5˚ .
- Earth’s tilt cause the sunlight to strike the
earth at different angles .
- (At any given time, each half of the earth gets more or less
sunlight, that causes the different seasons)
The Earth’s axis

13. What causes the seasons to happen on Earth?
- The Earth’s tilted axis & the revolving of the Earth
around the sun causes the four seasons to happen
on Earth.
The Four seasons
How?

14. In June: The northern hemisphere is tilted
towards the sun. The light strikes at steep
angles, so it will have summer
In Dec.: The northern hemisphere is tilted
away from the sun. The light strikes at low
angles, So it will have winter
-During summer daylight hours are longer than winter and
nighttime hours are shorter.
- At the equator the temperature and day hours stay almost the
same throughout the year