Waves and Tides   The two most common and regular motions of the oceans are the ‘Tides’ and ‘Waves’. The Moon’s gravitational pull on the Earth causes the level of water in the oceans to rise and fall, thus causing high and low tides. When the Moon is opposite an ocean, the water is pulled upwards thus causing a high tide. This happens on the opposite side of the Earth as...

Oceans and Seas The oceans are vast expanses of water which cover about 71 percent of our planet and separate the continents. Millions of years ago when the Earth cooled from it’s molten state, water vapour in the atmosphere condensed to form water which collected in deep trenches on the surface, thus forming the oceans. Water on the land flowed into them in the shape of rivers, which carried with them...

The Continents Twenty nine percent of the Earth’s surface is land and about 200 million years ago it was a single mass surrounded by the oceans called ‘Pangaea’. In the year 1912 a German meteorologist called Alfred Wegener suggested that this single mass of land was in reality located above large flat pieces of rock. called ‘plates’, which had large cracks m them. With the passage of time, about 130 million...

The Earth’s Atmosphere It is the Atmosphere which has made life possible on the Earth, it protects us from the harmful rays of the Sun and keeps out the cold of outer space, and it also provides a host of other conditions because of which life can thrive on this planet. It has various layers and surrounds the Earth like an insulator, 78% of it is composed of Nitrogen, 21% of...

Earth’s Crust and Inner Core Millions of years after it’s origin, the Earth still has a molten core, about 2600 km thick, with a temperature in the range of 4,700° centigrade. Above this inner core is an outer core which is about 2,000 kms thick and is made up of molten iron with temperatures in the range of 2,2000 centigrade. The ‘Mantle’, as it is called, which surrounds both the inner...

Our Satellite the Moon It was believed earlier that the Moon was a piece of the Earth which broke away millions of years ago. This theory went through a change as new facts about the Moon were revealed with the passage of time. Today it is believed that the Moon was formed from the same cloud of dust from which the Earth was formed. The Moon also went through the same...

The Earth Our planet, the Earth, is a part of the Sun’s family and is located about 150 million km away from it. The Sun was formed due to the contraction of a cloud of gas and dust, the remaining part of this cloud eventually formed the other planets in the same manner. The Earth took close to 100 million years to become a glowing ball comprising of molten rock. The...

The Ozone Layer The Earth’s atmosphere comprises of various layers, the first which extends up to 10 km from the Earth’s surface is the Troposphere’. Above this is the ‘Stratosphere’ which is between 10 and 50 km, then the `Mesosphere’ between 50 and 80 km and finally there is the  ‘Ionosphere which is located between 80 and 501) km from the Earth’s surface with temperatures as high as 2000° centigrade. About...