By Admin, 2017-06-09 Friday
The earth is an oblate spheroid(ball flattened at the poles), i.e. almost spherical, flattened a little at the poles,and with a slight bulge at the centre(equator). The spinning(rotating)of the earth at a high speed as caused its mass to bulge at the equator and sinking at the poles.
STRUCTURE OF THE EARTH
The earth is made up of a number of concentric layers of material as in the bulb of a onion.
These Layers are
↬ Crust
↬ Mantle
↬ Outer Core
↬ Inner Core
COMPOSITION OF THE EARTH
The earth is made up of more than 100 different elements. The important ones are:
Oxygen 46.6 %
Silicon 27.72 %
Aluminum 8.13 %
Iron 5.00 %
Calcium 3.63 %
Sodium 2.83 %
Potassium 2.70 %
Magnesium 2.09 %
Others 1.3 %
The earth has four distinct spheres:
1. Lithosphere: Top crust which includes land surface and ocean floor.
2. Hydrosphere: Water surface which includes oceans, seas, rivers and lakes.
3. Atmosphere: The cover of air that envelops the earth's surface.
4. Biosphere: The region where life exists.
THE EARTH DIAMETER
At the equator:
12,756.2 km
At the poles:
12,713.54 km
Mean diameter:
12,734 km
Equatorial radius:
6,377 km
Total surface area: 509,700,000 sq.km
Total land area(29.08%): 148,400,000 sq.km
Total water area(70.92%): 361,300,000 sq.km
Mean distance from the sun:1,49,407,000 sq.km
Time for rotation on its own axis: 23 hrs, 56 min & 4.09 sec
Period for revolution around sun: 365 days, 6 hrs, 9 min & 9.54 sec
EARTH'S MOVEMENTS
The earth has two types of movements: Rotation: The earth spins on its own imaginary axis from west to east once in 24 hours. It is also called diurnal or dally motion,which causes the formation of day and night.
Longest days & Nights
Northern hemisphere:
* longest day: June 21
* shortest day: Dec 21
Southern hemisphere:
* shortest night: Dec22
* longest night: Jun 21
Days and nights are equal at the equator throughout the year because the circle of illumination always divides the equator into equal parts.
The earth is an oblate spheroid(ball flattened at the poles), i.e. almost spherical, flattened a little at the poles,and with a slight bulge at the centre(equator). The spinning(rotating)of the earth at a high speed as caused its mass to bulge at the equator and sinking at the poles.
STRUCTURE OF THE EARTH
The earth is made up of a number of concentric layers of material as in the bulb of a onion.
These Layers are
↬ Crust
↬ Mantle
↬ Outer Core
↬ Inner Core
COMPOSITION OF THE EARTH
Oxygen 46.6 %
Silicon 27.72 %
Aluminum 8.13 %
Iron 5.00 %
Calcium 3.63 %
Sodium 2.83 %
Potassium 2.70 %
Magnesium 2.09 %
Others 1.3 %
The earth has four distinct spheres:
1. Lithosphere: Top crust which includes land surface and ocean floor.
2. Hydrosphere: Water surface which includes oceans, seas, rivers and lakes.
3. Atmosphere: The cover of air that envelops the earth's surface.
4. Biosphere: The region where life exists.
THE EARTH DIAMETER
12,756.2 km
At the poles:
12,713.54 km
Mean diameter:
12,734 km
Equatorial radius:
6,377 km
Total surface area: 509,700,000 sq.km
Total land area(29.08%): 148,400,000 sq.km
Total water area(70.92%): 361,300,000 sq.km
Mean distance from the sun:1,49,407,000 sq.km
Time for rotation on its own axis: 23 hrs, 56 min & 4.09 sec
Period for revolution around sun: 365 days, 6 hrs, 9 min & 9.54 sec
EARTH'S MOVEMENTS
The earth has two types of movements: Rotation: The earth spins on its own imaginary axis from west to east once in 24 hours. It is also called diurnal or dally motion,which causes the formation of day and night.
Longest days & Nights
Northern hemisphere:
* longest day: June 21
* shortest day: Dec 21
Southern hemisphere:
* shortest night: Dec22
* longest night: Jun 21
Days and nights are equal at the equator throughout the year because the circle of illumination always divides the equator into equal parts.
No comments:
Post a Comment