...salam to all today's there is a continuation of the thing about water... this was taken from kids geo site where kids can learn about our beloved planet earth ... there's games as well .. for those with school going kids, this is one amongst many good sites for learning ...Anyways hope we all can learn something from this post...Thanks
p.s. next post could be about music or a video clip of some sort and i apologize if the pictures from some earlier post doesn't appear..trying to fix it.
The Pacific Ocean
The largest of all the Earth’s oceans, the Pacific Ocean covers twice as much space as any other ocean, and more space than all the continents put together.
This vast body of water extends upward touching the Arctic ocean, and also extends down to the shores of Antarctica. The bulk of this ocean however lies along the warm tropics. This makes the majority of the Pacific’s water warm.
The Pacific Ocean has the deepest average depth, and is also home to the deepest trenches on Earth. Much of the Pacific is dotted with small volcanic islands, such as Hawaii, Tonga, and Samoa.
The Pacific Ocean is notorious for bad weather. Some of the most powerful storms are brewed within its waters.
The Atlantic Ocean stretches from the Artic Ocean, downward to the shores of Antarctica. This makes it the same size from North to South as the Pacific Ocean. However, from East to West, the Atlantic Ocean is only about half as wide as the Pacific.
The Indian Ocean
The Indian Ocean lies between Africa on the West, Australia on the East, Asia on the North, and Antarctica on the South. 90% of this ocean lies to the South of the Equator.
The Indian Ocean is just slightly less deep than the Atlantic Ocean.
The Arctic Ocean
The Arctic Ocean is both much smaller than the other oceans, as well as more shallow. This ocean is connected to the Pacific and Atlantic oceans via small gaps between continents.
This ocean is also much colder than the other majority of the other oceans, with much of the water covered in a frozen ice cap.
Characteristics of Ocean Water
The ocean can extend in some places down to depths of several miles. However most of the action takes place in the first couple hundred feet. Below this depth it is too dark, cold and murky for much to happen. Across the entire planet, the Earth’s oceans are believed to be basically the same below the first couple hundred feet.
Above this depth, where sunlight reaches, the traits found change dramatically from one location to another. Characteristics such as temperature, turbulence, and salinity can be very different from location to location.
The Ocean’s Salinity
As discussed earlier in this chapter, one of the important characteristics of water is that it is a superb solvent. This means that other substances such as minerals can dissolve quickly and easily into it.
The ocean contains a soup of the many different minerals found across the surface of the Earth, all dissolved into the water. These minerals make up about 3.5% of the total volume of the Earth’s oceans.
By far, the most common mineral found dissolved in sea water, is salt. Have you ever tasted ocean water? What does it taste like? Because salt is the most common mineral in the waters of the oceans, it is no surprise that the ocean tastes salty.
The amount of salt dissolved in the waters of the Earth’s oceans, or the salinity of the oceans can vary greatly from location to location. This salinity is dependent on two important factors. Firstly, the amount of evaporation taking place, and secondly, the amount of fresh water being added.
As water evaporates, it leaves the salts and other minerals behind. This causes the water left behind to be more salty. As fresh water is added, either via rivers, or via rainfall, the salinity of the ocean in a particular location is decreased.
As one would expect, the further you travel from the Equator, the colder the ocean waters generally become. Near the Equator surface water temperatures can be as high as 80 ° . Near the poles, the temperature drops to a chilly 28 °.
The Western side of oceans are usually warmer than the Eastern side. This is due to the way in which the both atmospheric and oceanic currents move water from the equator towards the poles on the Western side of oceans, and from the poles towards the equator on the Eastern side of oceans.
Movement of Ocean Water
The waters of the Earth’s oceans are for the most part in liquid form. What happens when you take a half full bottle of water and shake it up? Do you see the bubbles swirling around the water bottle rapidly? While liquid water molecules do generally attract one another, forming a body of water, molecules within that body of water are free to move about, becoming thoroughly mixed up.
The waters of the Earth’s oceans can be mixed up by a number of forces, including wind, splashing against a rocky shore, swimmers, boats, etc. However, the items mentioned above create only a very minimal amount of mixing. Three important forces create a much more prevalent mixing of the ocean’s waters, causing the water to move about from one place to another, as though a giant were shaking them, in the same manner that you shake a water bottle.
These forces are waves, currents, and ocean tides.
Ocean Waves
The surface of the Earth’s oceans are is in constant motion, moving up and down, in the form of waves. If you have been to a beach, you have witnessed waves first hand.
Waves form, as energy is transferred from molecule to molecule across the surface. In general, the water molecules move very little. It is only the energy that actually moves.
However, as waves break across a shore, or crash in violent storms, they can be the source for great mixing of an ocean’s water.
There are a number of ocean currents found around the Earth. A current is like a vast river within the ocean, flowing from one place to another. These currents are caused by differences in temperature, differences in salinity, and by wind. Currents are responsible for a vast amount of movement of the water found in the Earth’s oceans.
Tides
By far the most important factor, effecting the movement of water across the ocean are tides. Tides are great bulges of water, caused by the gravity of the Moon, and Sun. Attracted by gravity, these bulges move around the Earth’s oceans, causing water levels to rise and fall. Typically water will rise for about six hours, followed by six hours of falling water depths.
The Earth’s Ice
Second only to the ocean in the amount of water storage, the ice of the Earth makes up more than twice as much water as all other types of water storage, including ground water, lakes, streams, etc. It has been estimated that there is enough water locked up in the form of ice to sustain all the rivers and streams of the Earth for nearly 1,000 years.
This ice is found around both the North, and South poles, and is always fresh. This is because, irregardless of whether it formed by freezing rain, or sea water, the salt is not taken into the ice crystals as they form.
In addition to the vast ice caps found at the top and bottom of the Earth, there is also vast amounts of frozen water underground. This frozen soil is known as permafrost, and is found in Canada, Alaska, and Siberia.
Surface Water
Water found on the surface of continents and islands are referred to as surface water. Surface water makes up only one fourth of one percent or 0.25% of the total water found on Earth. This water is found in rivers, streams, lakes, springs, and swamps, and is extremely important to the lives of all land dwelling animals, including humans.
Lakes
Lakes contain about 90% of all the surface water found on Earth. (not including oceans) Lakes form when water finds its way into a basin. In order to continue existing, lakes must have a continual source of new water, otherwise they will eventually dry up.
Most lakes contain fresh water. However, in some cases, the water found in a lake can become salty, just like the ocean. This happens when a lake does not have a stream, either above ground, or underground draining water away from it. As water enters a lake, it carries minerals with it. As this water dissolves, it leaves the minerals behind.
Most lakes only last a few thousand years, and then disappear. This is because as streams and rivers carry water into the lake, they also carry sediment. This sediment slowly fills the lakes, causing them to become shallower. At the same time outbound streams cut deeper and deeper channels, causing the lakes to drain more quickly.
Many lakes, are man made. These are referred to as reservoirs. Reservoirs allow cities and nations to store water for later use. Most of these reservoirs are small in size, but some are very larger, spanning several hundred miles.
Swamps
A swamp is similar to a lake but it is much shallower. Swamps are covered with water, but this water is shallow enough to allow plants to grow, reaching the surface.
Swamps are generally dominated by water tolerant trees.
Marshes
Marshes are similar to swamps, but instead of trees, they are dominated by grasses and reeds. They are generally rich with live, harboring many kinds of frogs, turtles, fish, and bird life.
Rivers And Streams
Geographers generally refer to all rivers and streams as streams, regardless of how big they are. Streams have an important job. They drain the landscape, and move water, and minerals towards the Earth’s oceans.
As water drains it generally begins in small creeks, which flow into larger and larger streams, and eventually into powerful flowing rivers. The largest river on Earth is the Amazon, which drains much of South America. The largest river in North America is the Mississippi River, which drains over 40% of that continent.
Underground Water
Locked deep within the lithosphere, or surface of the Earth, is found many billions of gallons of water. Almost anywhere on Earth, it is possible to dig down, and find a supply of fresh drinkable water. Almost all of this water was deposited over millions of years by the many rain and snow storms that have visited the surface of the Earth.
Most ground water lies within ½ miles of the surface of the Earth. However, scientists have found water at a depth of more than six miles.
