(WOE) Where is All The Water Lesson
Where is All the Water?
About 70 percent of the Earth's surface is covered with water. Oceans hold about 96.5 percent of all Earth's water. But we can also find water existing in the air as water vapor, in rivers and lakes, in icecaps and glaciers, in the ground as soil moisture and in aquifers. Even you and your pet consist of some water.
See description of diagram Links to an external site.
The image above shows pie charts representing the Earth's water supply. As can be seen in the top pie, the vast majority of the Earth's water is contained in the oceans and seas, and only 2.5% to 3% of the Earth's water is freshwater. Now looking at just the freshwater portion (middle pie), most of that (79%) is frozen in glaciers and ice caps at the North and South Poles, part (20%) is groundwater, and only 1% is accessible surface freshwater. From the bottom chart, of that small amount of accessible surface freshwater, 53% is in rivers and streams, and 8% in the atmosphere. So, water in freshwater lakes is about 52% of the 1% accessible water, of the 3% of the total which is freshwater, or about 0.015% of the total water in the Earth.
There are a total of 5 oceans, and they are the Arctic, Pacific, Atlantic, Indian, and the Antarctic Ocean. Out of these five, there are three major oceans, the Atlantic, Pacific, and the Indian Ocean. They account for 90 percent of the area covered by oceans.
Consider the pie graph below
Remember, water covers approximately 70 percent of our world's surface. Yet only 2.5 percent of the Earth's water is fresh and thus suitable
for consumption. Not only that, but of that 2.5 percent, more than two-thirds is locked away in glaciers and not particularly able to help meet the growing demands of society. By far, the most abundant and available source of fresh water is underground water supplies or wellsprings known as aquifers.
The percentages of earth's land surface can be divided into different types: 20% covered by snow land, 20% mountains, 20% dry land, 30% good land that can be farmed, 10% land doesn't have topsoil.
See description of diagram Links to an external site.
Watch the following short video.
Ocean Salinity
All animals, plants and humans need water in different percentages to sustain life. The human body is 66% water. We can't survive long without water. We have learned that the earth has far more ocean water than freshwater. Various animals and organisms can live in ocean water. But ocean water cannot have the positive effects that clean, fresh water has on the human body. Ocean water needs to undergo a desalination process to become drinkable. This solution has already been implemented on a larger scale in countries where fresh water resources are scarce.
The salt in ocean water is mostly sodium chloride which is the chemical name for table salt.
Salinity is the measure of the amount of salt dissolved in a liquid. The average salinity of seawater is 35 parts per thousand (35 ppt). This means that 35 units of salt are in every 1,000 units of seawater. This is the average. In areas of dry climate, like the Mediterranean Sea, the salinity is about 38 ppt. The increase in salinity is due to a higher rate of evaporation.
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