Every season, trees add a new ring of growth to their trunks
Clouds are made of water droplets, ice, crystals, particles of dust and air
Warm air can hold more water vapour than cold air
The age of Earth is calculated as 4500 million years.
Ozone is measured in Dobson Units
The amount of ozone in the atmosphere is expressed in ppm/dobson units (chk)
Air is composed of nitrogen (78.08%),oxygen (20.95%),argon (0.94%) and carbon dioxide (0.03%).
Nitrogen gas dominates the earth’s surface.
Weathering takes place more quickly in warm, wet area than in cold and dry regions.
An atmosphere is a blanket of gas that surrounds a plane.
Earth’s atmosphere is over 1000 kilometers deep, but most of it is in the 30 kilometers closest to Earth.
Weight of the air pushing on us is known as atmospheric pressure.
Atmospheric pressure is equal to 14.73 lbs per sq. inch.
Atmospheric pressure decreases with height.
In nature the nitrogen of the atmosphere is made available for the plant growth through the activity of bacteria called nitrogen fixation of bacteria in roots of plants.
Earthworms provide nitrogenous wastes.
Ozone is found in stratosphere b/w 20 to 50 km.
The tidal effect of Moon on the surface of Earth is less that that of Sun because Moon’s gravitational pull at Earth’s surface is less as compared to Sun’s gravitational pull.
Tidal effect of sun is 146% of moon.
Injurious ultraviolet radiations are mostly prevented from reaching the earth as these are absorbed mostly by Ionosphere.
510 million square kilometers is the total surface area of the earth.
At 7050 km per hour, Sun rotate on its axis.
The northern polar lights are called Aurorae Borealis
Southern polar lights are called Aurorae Australis.
The pulsating universe theory explains the evolution of universe.
