20th May 2016
Lightning bolts are electric discharges that originate in the clouds during a storm and travel to the earth’s surface. About 100 lightning bolts strike the earth every second. One bolt can contain up to one billion volts of electricity.
19th May 2016
Only 3 per cent of earth’s water is fresh, the rest 97 per cent is salt water. Of that 3 per cent, over 2 per cent is frozen in ice sheets and glaciers. It means less than 1 per cent fresh water is found in lakes, rivers and underground. Water, indeed is a scarce resource.
19th May 2016
The earth is divided into three layers: the upper crust, the middle mantle and the innermost core. The upper crust is made of solid plates, called tectonic plates. Some plates are under the ocean too. The mantle is semi solid and the tectonic plates slide over the mantle, causing an earthquake. Every year over one million earthquakes shake the earth.
6th May 2016
A raindrop falls on the earth with varying speeds depending on its size and weight. The gravity acts on the falling raindrop and the drop picks up speed. But due to air resistance, which is generally proportional to the velocity, the raindrops attain a terminal speed. A larger raindrop would fall much faster at 9 metres per second whereas a smaller raindrop will fall at a much slower speed of 2 metres per second.
4th May 2016
The Nile is one of the most interesting rivers of the world owing to the ancient Egyptian civilization, which is known as the ‘Gift of Nile’. The river originates in the well-watered regions of northeastern Africa and proceeds to drain northwards in the Mediterranean Sea. It is known as the world’s longest river. Although different sources provide different measurements of the river, according to some experts it is 6,650 kilometres long.
2nd May 2016
Water falls on earth in the form of precipitation, such as snow or rain. Rainfall is the main form of precipitation. The amount of rainfall may vary from region to region. It could be 0.1 inch per year in deserts and 900 inches per year in the tropics. If a one inch rainfall occurred in one acre of land, it would weigh 113 tons.