The water coverage of the Earth
Our planet, the Earth as we all know is covered by water. But how much?
Added together, all the oceans and seas cover around two thirds of the earth’s surface. The oceans are huge masses of water between continents – but all linked together to form one mass.
The area of the covered water would increase still more if we were to count the frozen glacier regions. The quantity of water on the earth does not always stay the same. By the time The Ice Age ended over two million years ago the quantity of water on the Earth reduced so much that the level of the seas went down by about 140 meters. This is the reason, and this explains how it is that fossils of fish have been found well inland, mountains and all. Because these were the ancient inhabitants of the prehistoric seas, so there is not that much water on the Earth today as there used to be.
But if all the glaciers on Earth were to melt, the level of the seas would go up. And this will cause another level of matter also. When the sea level gets high the landside will reduce and the small island will get smaller and smaller which causing the reduction of the Earth’s surface.
How is a glacier formed?
In place where there is a lot of snow, and the temperature does not rise much more than freezing, even in summer, the snow cannot melt.
Instead, it accumulates and turns into ice – and when the ice accumulates it forms a glacier.
Like a great river, a glacier may eventually slide down a slope, forging a path to form a U-shaped valley.
Rocks, boulders, and stones fall in and get carried along – and when the frond of the glacier gets beyond the snow- covered areas and the ice begins to melt, all these rocks and stones are left in a rounded heap, called a “moraine”.
The Salty Sea
Why is the sea salty? Although the Earth is covered mostly with the Sea, we are not capable of using the sea water. Well, all water contains salt. The taste of the salt depends on the quantity and the water in which it dissolved. In the sea, the saltiness depends on several parameters. The temperature of the sea, the rivers flowing into it and the currents. The higher the temperature, water evaporates, and the salt gets very concentrated. The rivers always bring the clear water. So, a sea which has a lot of river water is having less salt amount than a sea where a few rivers flow. The current, is the reason to the salt to get mix with the water and so dilutes the quantity of salt.
The saltiest sea is the Dead Sea. In fact, it is an enormous lake, in a very hot region of the Middle East completing the parameter of temperature. So, its waters evaporate a lot and as no rivers flow into this sea, the Dead Sea is very salty indeed! The saltiness of the Dead Sea is enough to stop almost everything growing anywhere else, which is why it is called the “Dead” Sea.
The salts mostly present in sea s are chorine and sodium – sodium chloride, a compound of chlorine and sodium is the salt we use at home. Zinc, Magnesium, Calcium and Potassium, as well as smaller quantities of other slats.
The color of the Sea
What color is the sea? Sea waters are clear, but the surface color, which we can see when we look at the sea is depending on the reflection of the sky. So, with a grey sky, the sea will be grey. And most of us have seen the leaden color of the sea in bad weather. But deeper the sea, the deeper the color. It will become blue, then gradually darkening into violet. The light from the rays of the sun cause this. They made up of all the gradual changes or graduations in color.