Salt is a mineral that is found both in solid and liquid form. The liquid is called brine. Salt contains two elements, chlorine and sodium, and is known chemically as sodium chloride. Mineralogists call salt that is found in mines halite. Salt is essential to health. Body cells must have salt in order to live and work. Salt makes up about 0. 9 percent of the blood and body cells. It has been estimated that there are more than 14,000 uses for salt. Most people think of salt chiefly as a seasoning for food. But less than five percent of the salt produced in the world each year is used in this way.
Meat packers, chemical companies, hide and leather processors, and food processors, such as manufacturers of dairy products use salt and its by-products. Farmers feed salt to livestock and use it as a preservative for hay in storage. Factories, plants, laundries, and other industrial institutions use salt to soften water and condition it. Salt is also used to hold firm the materials used in building secondary roads. It is also used in heat-treating, smelting, and refining metals. There is a little more than pound of salt in each gallon (or 30 grams in each liter) of seawater.
It has been estimated Gagnard 2 that if all the oceans dried up, they would leave about 4,419,300 cubic miles of rock salt. That would be enough to cover all the United States except Alaska and Gawaii with a layer of salt more than 1 miles deep. Salt was first taken from the sea by scooping out shallow holes along the seashore. Waves, breaking along the shore, filled the holes with brine. The sun and wind causes the water in the brine to evaporate, leaving behind the crude salt. This process was known as the solar method. The solar method is still used.
But, to speed the process of evaporation, the brine is put in enormous iron pans placed over extremely hot fires. Salt obtained in this manner is very pure. But it has been estimated that a single salt plant should contain at least 5,000 acres of land to make the solar system practical. Salt is found beneath the ground in almost every part of the world. Sometimes the salt lies near the surface or even above it. Rocks of salt that appear above the ground are called salt licks. However, most salt veins lie far beneath the earth’s surface and the salt must be mined in much the same way that coal is mined.
Shafts are sunk and elevators are installed in them. The miners descend, and by means of compressed air drills and electric crushing and shoveling machines, break loose the halite. Elevators take the salt to the top of a tippler, a building that may be eight stories high. On its way down Gagnard 3 through the building, it goes through crushers, passes over screens that separate it into crystals of various sizes, and is put in sacks or bulk carloads. These are shipped to consumers. But, Much of the salt produced in the United States comes from salt wells.
This salt is dissolved by water and pumped to the surface. A salt well is drilled in much the same way that a water or oil well is drilled. The salt well gas a double pipe, or casing, sunk into it. One pipe is inside the other, leaving space between the two. Pure, fresh water is pumped down through this space to the salt vein below. It forms a solution of salt and water, which is heavier than pure water. The brine sinks to the bottom of the well. The solution is then forced up the inner pipe by the pressure of the fresh water that continues to come down.
When a vein of salt lies very deep, air pressure forces the brine to the surface. The brine that comes from the well contains only the impurities that dissolve in water. Solid impurities are left at the bottom of the well. The brine is refined in about the same manner as sea salt. More than 12 percent is taken from the sea, over 29 percent from mines, and about 57 percent for wells. The salt ammonium nitrate is used in fertilizers to add nitrogen to soil. Plants and animals need various salts in order to stay healthy. Gagnard 4 Water is the most common substance on earth.
It covers more than 70 percent of the earth’s surface. It fills the oceans, rivers, and lakes, and is in the ground and in the air we breath. Water is everywhere. Without water, there can be no life. Every living thingplants, animals, and manmust have water to live. In fact, every living thing consists mostly of water. Your body is about two-thirds water. Most scientists believe that life itself began in waterin the salty water of the sea. The salty taste of our blood, sweat, and tears suggests that this might be true. Ever since the world began, water gas has been shaping the earth.
Rain hammers at the land and washes the soil into rivers. The oceans pound against the shores, chiseling cliffs and carrying away land. Rivers knife through rock, carve steep canyons, and build up land and cut down mountains. Water helps keep the earth’s climate from getting too got or too cold. Land absorbs and releases heat from the sun quickly. But the oceans absorb and release the sun’s heat slowly. So breezes from the oceans bring warmth to the land in winter and coolness in summer. Today, more than ever, water is both slave and master to man.
We use water in our homes for cleaning, cooking, bathing, and carrying away wastes. Our factories use more water than any other material. We use the water in rushing rivers and thundering waterfalls to produce electricity. But, Gagnard 5 most importantly we use water to irrigate dry farmlands so we can grow more food. Only about 3 percent of the world’s water is fresh water and about 97 percent is in the oceans. This water is too salty to be used for drinking, farming, and manufacturing. Most of the plants that man raises need great quantities of water.
For example, it takes 115 gallons of water to grow enough wheat to bake a loaf of bread. Man raises most of his crops in areas that have plenty of rain. Plants take in water through their roots. They then pass it out through their leaves into the air as a gas called water vapor. Winds carry away the vapor and the liquid water is gone. The United States uses about 110 billion gallons of water a day for irrigation. This is enough water to fill a lake 5 miles long, 1 mile wide and 100 feet deep. About 41 percent of all the water used in the United States is for irrigation.