How does electricity reach our homes?

Electricity enters our homes, schools, factories, warehouses through copper cables from powerful generators in power plants.

These plants burn coal or oil, or use nuclear reactors or the power of waterfalls to produce the energy needed to run the generators.

Powerful loads of current come from these generators and are reduced by transformers before they reach our homes and factories.

The electrical current produced is a continuous flow of small particles called electrons. This flow of electrons can be activated or deactivated by means of switches. When you turn on an electric light switch, a television, or any other appliance, the electric current is given a message to start flowing. When the switch is lowered, the current flow stops.

Sometimes that current flow stops without touching the switch. This occurs when wires or circuits overload when there is too much electricity, and a device or fuse in the house automatically breaks the circuit to prevent damage to the wires or even a fire in your home.

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Is uranium found in nature?

Uraninite

Uranium is not an artificial substance, but a natural element, just like oxygen, iron, or gold. It is found in the Earth's crust, in seawater, and even in the tissues of living things. In fact, there is more uranium in the Earth's crust than other elements such as silver, mercury or iodine!

But uranium is never found in nature in its pure form. Many tons of uranium ore have to be mined to produce just one kilogram of uranium, and this uranium is not pure, but mixed with oxygen.

This uranium oxide must then be purified to obtain pure uranium. But the process does not end here, but the uranium has to be purified again, before it is the right type for use in atomic bombs and nuclear power plants.

Pure uranium is a white metal, which looks like steel. It is very heavy - the heaviest of all natural elements, in fact; one cubic foot of uranium weighs more than 450 kg!

The largest uranium deposits are in Canada, Zaire, Australia and the United States. The largest existing uranium mine is in Namibia, in southwest Africa.

Man has been using uranium for more than 2,000 years, but for 1,900 years, it was only used as a pigment in the manufacture of glass and paint in China!

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Why is uranium used in atomic bombs?

Uranium is a metal used in atomic weapons and nuclear power plants because it is a radioactive element. The atoms of a radioactive element disintegrate over time, losing particles from its nucleus and releasing significant amounts of energy.

Normally, this process occurs in some uranium atoms at once. But in an atomic bomb, the atoms split up quickly, releasing large amounts of energy instantly.

Uranium atoms disintegrate inside an atomic bomb because they are hit by subatomic particles or neutrons. When a neutron hits the nucleus of a uranium atom, it causes the nucleus to split.

This produces energy and sends the particles of the uranium atom that crash into other atoms, whose nuclei disintegrate at the same time, sending more energy and particles, and so on. This process is called a chain reaction.

Once the chain reaction starts inside the bomb, the process continues until most of the atoms have split. This happens in a fraction of a second, so all the uranium energy is released.

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When was geothermal energy first used?

The first geothermal power plant was built in 1904, in northern Italy, where steam emanated at temperatures between 140 and 260 degrees Celsius. The gas was transported to turbines that in turn activated the generators.

In New Zealand, Philippines, United States and Mexico there are geothermal plants in places where the terrestrial heat emerges in natural form. but in the majority of the cases it is necessary to perforate to use the energy. Sometimes only dry hot rocks are found, the heat of which can be harnessed by injecting water and then recovering it in the form of steam. This drives turbines and generates electricity.

To exploit the energy, two wells must be drilled: one for pumping cold water and the other for the pressurized water to come out. The water passes from one well to the other through the fissures caused in the rock by explosives. Even when the water reaches very high temperatures, the pressure at the bottom prevents it from boiling. But when it returns to the surface, at normal atmospheric pressure, it evaporates instantly and is able to drive the turbines.

In many places geothermal energy can be harnessed, but several problems are faced. For example, it is necessary to remove minerals from hot water so that they do not scale pipes or corrode turbines. On the other hand, it has been found that only one third of the pumped water returns to the surface, the rest is lost. The third problem is drilling deep enough. If these obstacles are overcome, the geothermal potential could be exploited in many parts of the world.

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How does wind generate electricity?

The wind has enormous potential to generate electricity. It is estimated that there are enough sites in Europe to install some 400 000 wind-powered generators, which would be enough to produce three times as much electricity as is required today in all the countries on that continent.

Modern generators of this type differ from the old windmills in that they basically consist of giant two or three blade propellers, called rotors, mounted on top of steel or concrete towers. The rotors rotate an axis that drives an electric generator.

The size of the blades and the height of the tower determine the amount of energy that can be generated. Generally, the wind is stronger at higher altitudes, and the force used depends on the swept surface of the blades. If the length of the blades is doubled, the energy is quadrupled. The most important thing is the wind speed: if the force of the wind doubles, it produces eight times more energy, for example.

However, wind generators do not need violent gusts to function. Mostly designed to operate with winds from force 3 to force 10 (21 to 97 km/h) on the Beaufort scale. Above force 10 the machines are automatically switched off to prevent them from flying into pieces.

Usually these generators produce almost the same energy continuously. They have been designed to produce a stable amount of electricity rather than to take advantage of occasional bursts.

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How do waves generate electricity?

 The waves have long been used to generate energy. In the 18th century, several plants were built on Europe's coasts where the waves reached a reservoir with floodgates. These were closed when the tide was high; once it came down, the water could only escape from the reservoir by passing through a hydraulic turbine that turned to generate energy.

The same principle was applied to a power plant built in France in the 1960s. A dam was built in the estuary of the Rance River, Brittany region, with 24 machines that can function as turbines, regardless of whether the water flows in one direction or the other.

When the tide comes in, water accumulates against the dam until there is a 1.5 metre difference between the two sides. It is then passed through the electricity-generating turbines. As the tide goes down, the turbine blades turn and the water that returns to the sea generates electricity again.

The amount of electricity produced depends on the water level on both sides of the dam. The greater the difference in level, the more electricity is generated, because the water is under greater pressure and turns the turbines with greater force.

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How does a nuclear reactor generate electricity?

A handful of uranium provides as much electricity as 70 tons of coal or 30 barrels of oil. A nuclear reactor to power a city of one million people consumes only 3 kg of uranium per day, making it the most concentrated energy source used by man.

Uranium is one of the densest natural elements and its atoms are very unstable. The nucleus of the atom only needs a small "push" to disintegrate, and when this happens it releases large amounts of energy, in the so-called nuclear fission.

This "push" can be received from neutrons, particles much smaller than atoms, which collide with the nucleus and disintegrate it. During this process at least two more neutrons are produced, which detach from the atom and then cause other fissures, so that these can continue indefinitely.

The energy of fission can be released little by little, and used to heat water. The water vapour is used to activate an electricity generator.

This is how a nuclear reactor works.

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Can coal be turned into oil?

 In South Africa, where hard coal - mineral coal - is plentiful, it began to be converted into oil a few years ago.

Large quantities of coal are exposed to fire and for several minutes it is ground with a mixture of steam and oxygen at high pressure. This material burns and releases large amounts of carbon-rich gas and hydrogen, the basic constituents of oil.

Since coal contains only half as many hydrogen atoms as oil, it is necessary to add such an element to coal by means of water vapour. When coal burns, it generates enough energy to separate the molecules of steam into hydrogen and oxygen atoms. This achieves a balance between the two.

This resulting gas is "washed" with methanol to remove cyanide and sulfur. Then it goes to reactors in which, according to the chemical treatment applied, a certain final product is obtained. The reactors can produce oil, gasoline, liquefied gas, waxes and compounds such as aldehydes, acetones and alcohols. However, the process is costly.

What is geothermal energy?

What is geothermal energy used for?

 Geothermal energy comes from the heat of the Earth's depths. About 30 kilometers below the surface is a layer known as the earth's mantle. This is the source of the gas and lava that erupts from volcanoes. Springs and geysers, with temperatures above 250 degrees Celsius, are also heated by the mantle.

Because of its high temperature, the mantle is a promising source of energy, especially in areas where hot water is very close to the surface.

Iceland, a country that has a large number of volcanoes and springs, makes efficient use of this energy resource, about 85% of houses use it.

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Watt (unit of power)

   A watt is a unit of power— usually electrical power. This unit was named in honor of James Watt, the inventor of the steam engine. Although the watt is the standard unit of power in the metric system of MEASUREMENT, the kilowatt is more generally used. The kilowatt is simply 1000 watts.
   In the metric system, a watt is that amount of power used when a force of one newton acts through a distance of one meter in one second of time. In electrical terms the watt is equal to the power developed when one AMPERE flows under a pressure of one VOLT.

Natural gas

    Natural gas was formed millions of years ago by the earth's movement, tiny sea plants and animals, and sunlight. Natural gas has been found in underground rock cavities. It often seeps to the surface.
   Gas was produced by the chemical action of small sea plants and animals. The movement of the Earth's crust caused this material to be buried and subsequently to decay. Most natural gas consists mainly of METHANE, a combustible
   The deposits of natural gas are reached by drilling wells. Geologists are able to determine by soundings and by rock formations its approximate location. Fuel gas, gasoline, ink, synthetic rubber, perfume, drugs, and dyes are some of the natural gas products.

Energy

   ENERGY "How much energy he has," we say when we see a little boy jumping up and down. "What a lot of energy that takes," we say when we see an expressman carrying a heavy trunk up a flight of steps. All work and play take energy. Energy is the ability to make things move.
   Green plants make food for themselves. To do so they must have energy. They get it directly from the sun. As sunlight, which is one form of energy, shines on the plants, they are able to put water and carbon dioxide together to make sugar. People and all other animals get their energy from the sun, too, but secondhand. For they eat plants or animals that eat plants. Much of the food animals eat "burns" slowly in their bodies to produce muscular energy and heat, another form of energy.
   Water rushing over a dam can turn a big water wheel. It has energy because it is moving fast. A stick of dynamite can blow up a building. It has what we call chemical energy. Electricity, magnetism, and sound are among the other forms of energy. We can use them all to make things move.
   We are just beginning to harness still another form of energy—atomic energy. In time we may be using atomic energy to do most of the work of the world

Why don't we get all our electric power from water?

   While the water is free, the dams to trap it and the machinery to exploit it are not. In fact, they are very costly. As an example, Fort Peck Dam in Montana has nearly 40 times as much solid mate­rial, by volume, as the Great Pyramid of the ancient Egyptian king Khufu. The number of good hydroelectric sites is limited, and many of them are a long way from the places where power is wanted. Even with modern methods of transmitting electric power, the cost rises with distance.

Oils

   An oil is a fluid light enough to float on water. It will not mix with water but will combine with alcohol. It remains fluid at normal temperatures. This distinguishes the oils from fats, which are solid at normal temperatures.
   A few oils come from fishes and other animals, such as fish oils and fish-liver oils, whale oil and neat's-foot oil. The latter is processed from the feet of animals at meat-packing plants. Sperm oil from the whale is not a true oil but a liquid wax.
   Most of our useful oils are obtained from the ground, as are petroleum and other mineral products, or from plants.
   The ancient Chinese, Hindus, Egyptians, Greeks and Romans obtained vegetable oils by milling and pressing various plant parts. Today most vegetable oils are obtained by heating or steaming methods.
Many different kinds of plant life provide useful oils: almond oil (from the nuts), castor oil (from the seeds of the castor bean), coconut oil (from kernels of nuts), corn oil (from the kernels), cottonseed oil, olive oil (from the fruit), peanut oil (from the peanuts), and soybean oil (from the beans). Petroleum and the products made from it are used as fuels and in chemicals.
   Some of the important uses for oils of various kinds are in lubrication, flavoring, perfume, and medicines.

Gasoline

   Gasoline is one of the liquefied lighter fractions obtained from the distillation of petroleum, coal, natural gas, and oil-bearing shales and sands. Most gasoline today comes from petroleum. Only 125 years ago, before kerosene lamps were replaced by electricity. gasoline was not even a byproduct. Many refiners dumped gasoline into the streams of Pennsylvania or poured it out onto the ground to burn. Then came the automobile, and gasoline became the mam product, and kerosene the byproduct. With the increased demand for gasoline came changes in refining, and the 42-gallon barrel of crude oil that in 1918 produced only 10.6 gallons of gasoline in 1952 produced 17.8 gallons.
   The technology of the production of gasoline is in such rapid development that few generalizations long remain valid. In general, gasoline is produced by either distillation or conversion of petroleum. Conver­sión has branched off into thermal cracking, catalytic cracking, and polymerization, which is the reverse of cracking. "Natural gasoline" is a product "squeezed" out of natural gas. It is not in itself a natural gasoline, but it is mixed with the regular product to be sold in service stations.
   The octane number of a gasoline indicates the percentage of a certain type of antiknock gasoline, called iso-octane, that has been mixed into the product sold. Iso-octane is almost knockproof in a high-compression gasoline engine, while heptane, the old-style gasoline, is prone to cause knocks. Knocking is uncontrolled combustion and is therefore wasteful. In the 1920's engineers found that antiknocking properties could also be put into gasoline by the addition of tetraethyl lead.

What is Fuel?

   Fuel, except for atomic energy, is carbon formed by the action of the sunlight on growing plants. When carbon is burned, energy in the form of heat is released. The four commonest forms of fuel, in the order of their appearance on the stage of history, are wood, coal, gas, and petroleum. Out of these basic forms of fuel man has learned to develop a multitude of refined forms, such as charcoal from wood, coke from coal, washed or purified gas from natural gas, and gasoline from petroleum.
   The ability of various peoples to use fuel differs. In the world today the advanced nations are the ones that burn enormous quantities of coal, gas, and oil. The "backward" countries are relatively poor in the use of these fuels. As the standard of living in a society improves, greater amounts of fuel are used to provide food, clothing, shelter, and other consumer products, as well as transportation, warmth in the win­ter, and air conditioning in the summer. The increase in productivity of American farmers since World War I is significantly related to their increased use of fuel, especially gasoline.
   Fuel, as carbon in any of its multitudinous forms, is not the only source of energy. Electricity from water power is another source.
   Atomic energy may soon replace carbon as a fuel. One pound of uranium can produce five million times as much energy as one pound of coal.

Where are the largest oil reserves?

   Canada has the world's largest oil reserves: 6 billion bar­rels of crude oil, mostly in Alberta, and more than 1 trillion barrels of oil in tar sands (sands soaked with an oil-producing substance) in northern Alberta. Production of oil from the sands began in 1967, but the process costs at least $11 per barrel (versus $2 per barrel for crude oil). Saudi Arabia has reserves of 263 billion barrels of crude oil; Iraq has 113 billion barrels.
   Currently only about one-third of the oil in most deposits is recoverable. Improved extraction methods—rather than new discoveries—most likely will increase the amount of reserves. Large oil deposits are believed to exist in Antarctica's continental shelf, but twenty-four countries have agreed to limit the continent to scientific investigation; extraction of oil, natural gas, and other minerals is banned by treaty until 2041.

Where are the largest natural gas reserves?

   Russia holds the world's largest supply of natural gas. The country has 38% of proven reserves, more than 1,700 trillion cubic feet. Iran is in second place, with 812 trillion cubic feet.
   Natural gas, a mixture of light hydrocarbons—mainly methane—and other compounds, is plentiful around the globe. It accounts for about 25% of the world's energy consumption—mainly for heating and generation of electricity—and is versatile. The use of natural gas offers various environmental benefits: natural gas is safer when transported, stored, and used; emissions of sulfur dioxide from natural gas are negligible; and emissions of nitrous oxide and carbon dioxide from natural gas are considerably lower than those from oil and coal. Increased dependence on natural gas could reduce the problems of acid rain and global warming.

Natural Gas fuel

Natural gas is one of the most widely used fuels in the world. Its advantages include automatic delivery, perfect heat control, and freedom from dust, ashes, and smoke as well as from the labor and complicated machinery needed to handle solid or liquid fuels. Its principal disadvantage is that it is difficult to store under pressure and is therefore not a suitable fuel for automobiles, locomotives, ships, or airplanes.

Natural gas is composed principally of methane, the lightest of the hydrocarbons, but includes small quantities of propane and butane, also other hydrocarbons of higher molecular weight. Natural gas, obtained from wells in the same manner as petroleum, is found both in petroleum wells and in many wells that contain only gas.

Dirty fuels

   Coal is the cheapest and most abundant energy source in the United States. However, coal is a dirty fuel. The smoke from burning coal contains large amounts of sulfur and carbon dioxide. Surface mining destroys the land environment. Drainage from surface mining pollutes water.
   Oil is the major source of gasoline and other liquid fuels used for transportation and heat. The United States must import 40 to 45 percent of its oil supply. Burning oil also adds pollutants to the atmosphere, such as carbon dioxide, sulfur dioxide, and other gases. The production and transportation of oil can also pollute the environment, especially if an oil spill occurs.
   Natural gas is the cleanest-burning fossil fuel. It generates fewer air pollutants and less carbon dioxide than other fossil fuels do. Gas is an efficient fuel and is used a great deal in industry, transportation, and power generation.