The Earth has two movements: rotation and revolution. Rotation is the Earth spinning on its axis every 24 hours, causing day and night. Revolution is the Earth orbiting the Sun every 365 days, causing seasons and years. Due to these movements, different parts of the Earth receive varying amounts of sunlight, influencing climate zones and seasons. The tilt of the Earth's axis and its position in orbit also affect the length of daylight and temperature changes throughout the year.
2. The Earth’s movements in the
Universe
As a planet the Earth
has two movements:
It rotates on its axis.
This movement is
called Rotation.
It orbits around the
Sun. This movement is
called Revolution.
3.
The Earth rotates
around its axis every
24 hours.
The Earth’s axis titls
at an angle of 23,5º
with its orbital plane
around the Sun.
This movement causes
day and night.
It is also useful for:
Orientation
Time zones
4.
The Earth rotates on
its axis every 24
hours.
This rotation causes
day and night as the
Sun’s light only
illuminates part of
the Earth’s surface
while the other part
is in darkness.
Thanks to rotation,
no particular part of
the Earth is too hot
or too cold,which
allows the existance
of life on Earth.
5.
As the Earth rotates on its axis it seems that the Sun moves
across the sky. It rises in the East and sets in the West.
In fact, it is not the Sun’s motion but the Earth’s rotation
which causes this impression.
Anyway, this apparent movement of the Sun is often used for
orientation on the Earth’s surface. Observing the Sun’s
“movement” we can identify 4 cardinal points:
North, South, East and West.
6.
Thanks to the Earth’s
rotation we divide the
Earth into 24 time zones
that correspond to the 24
hours of a day.
As the Earth is a geoid of
360º, each time zone is
15º across. There is one
hour in a time zone.
Spain’s point of reference
is the Prime or
Greenwich Meridian.
This is Meridian at 0º.
As we go east crossing
time zones, we set the
clock forward by one
hour.
As we go west crossing
time zones, we set the
clock back by one hour.
The Meridian opposite the
Prime Meridian is the
Meridian at 180º which we
call International Date
Line because we put the
date forward or back by a
day when we cross it.
All the places located on
the same time zone have
the same time.
7.
8.
As a planet, the
Earth orbits around
the Sun. This
elliptical orbit
aroun the star is
called Revolution.
It takes the Earth
around 365 days
and 6 hours to
complete a full
revolution around
the Sun.
The Earth’s
Revolution causes:
Years and leap
years
Seasons and a
changing length of
day and night.
9.
10.
It takes 365 days and 6 hours for the Earth to
complete a full revolution around the Sun.
So we have established the length of a year in 365
days.
Every four years we sum up the extra 6 hours
obtaning an extra day. This is called a leap year
as it has a length of 366 days.
11.
Depending on the position
of the Earth in its orbit
around the Sun some parts
of its surface are closest to
the star and some are
farthest.
The Sun’s rays reach
intertropical regions at a
direct angle while they
reach the poles at much
smaller angle. Because of
that, different parts of the
Earth’s surface receive
varying amounts of solar
energy.
This causes the Seasons:
Spring, Summer, Autumn,
Winter.
12. 21st march
Spring in
the Northern
Hemisphere.
Autumn in
the Southern
Hemisphere
21st June
Summer in the
Northern
Hemisphere.
Winter in the
Southern
Hemisphere
Winter in the
Northern
Hemisphere.
Summer in the
Southern
Hemisphere
Autumn in the
Northern
Hemisphere.
Spring in the
Southern
Hemisphere
23rd September
21st December
13.
When the Earth is
on its closest point
to the Sun, we call
it an Equinox. The
Sun’s rays are
vertical at the
Equator.
Spring equinox
takes place on the
21st March and
Autumn equinox on
the 23rd
September
14.
When the Earth is at
its farthest point in
its orbit from the
Sun we call it a
Solstice. It is when
the Sun’s rays are
vertical at the
tropics.
Summer solstice
takes place on the
21st of June. The
Sun’s rays are
vertical at the Tropic
of Cancer.
Winter solstice takes
place on the 21st of
December. The Sun’s
rays are vertical at
the Tropic of
Capricorn.
15.
Depending of the position
of the Earth in its orbit
around the Sun and the tilt
of the Earth, some parts of
its surface are closest to
the star and some are
farthest. Some of them
receive the Sun’s rays at a
direct angle and others at
a much smaller angle.
Because of that, different
parts of the Earth’s surface
receive varying amounts of
solar energy.
16.
17.
The Sun’s rays reach intertropical regions at a direct
angle for most of the year while they reach the poles
at a much smaller angle.
The tilt of the Earth’s axis of rotation plus the position
of the Earth on its orbit determines the existance of
climate zones:
Tropics
Temperate zones
Polar regions
18.
19.
The tropics are
located between
the Tropic of
Cancer and the
Tropic of
Capricorn. They
receive the greatest
amount of solar
energy through the
year which causes:
High temperatures
throughout the
year
Little difference
between the
seasons.
20.
The Temperate
Zones are located
between the tropics
and the Polar Circles.
So we have 2
temperate zones.
The number of
daylight hours
gradually falls
between the summer
and the winter
solstices. These zones
have 4 seasons:
spring, summer, autu
mn and winter.
21.
The Polar Regions are
located between the
Polar circles and the
Poles. They receive
little solar energy so
temperatures are
always very low.
There are big
differences between
the length of day and
night. The Sun is
visible in the sky only
for six months of the
year in each pole, in
the summer.
Anyway, even then the
Sun provides very little
heat because its rays
hit the polar regions at
a low angle.
