Category Forces of Nature

In direct current, electrons flow only in one direction, but in alternating current, electrons keep switching their directions. Due to significant advantages of alternating current over direct current, electrical power distribution is nearly all in the form of alternating current today. For many appliances, such as lamps, direction of flow of electrons does not matter; for others, such as computers, the flow needs to be uniform. Hence, a ‘rectifier’ is connected to a computer, which converts the alternating current into direct current.

European sockets provide electric current at 230 volts. Since, this voltage do not suffice to cover the large distance from the power plant to our homes, it is raised in the power plants with the help of transformers up to 380,000 volts. Locally, large substations or small ‘transformer houses’ transform the voltage to 230 volts. A transformer is like an electromagnet. The incoming high-voltage electric current generates a magnetic field in the coil. This permeates the neighbouring coil in the second electric circuit and generates a lower voltage: 230 volt.

By current we mean the flow of negative charge, i.e., the flow of electrons. Metals have lots of electrons. Hence, current flows in them, and they are good conductors. Substances such as air and glass are bad conductors. We need a source of power, such as a battery, to bring the electrons in motion so that a bulb can start glowing. The battery has a positive (+) and a negative (-) terminal. There are a lot of electrons at the negative terminal and only a few at the positive one. The flow of electrons from the negative terminal to the positive terminal is the current. It is measured in amperes (A). The greater the difference in charges between the two terminals, the stronger will be the flow of the current. This difference is known as the electrical voltage. It is measured in volts (V). 

Electricity plants convert the energy from the raw materials of the Earth into electrical current. This is done with the help of huge generators, which are driven by water, steam, or wind. Electricity is then distributed at a high voltage through cables laid in the ground or through overhead lines, on which often birds sit in swarms. Substations then produce electricity, which finally comes out of the sockets in our homes: 230 volts alternating current. However, many devices, such as computers, need direct current. Fuses protect us and our property from damages. 

Along with hydropower and fossil fuels, like crude oil and coal, the Earth has other resources of energy as well. These include the geothermal heat which comes from the depths of the Earth. The heat of the Earth normally comes out on the surface in destructive ways in many volcanic regions, and at other places such as Iceland this heat is released through ‘quiet volcanism’. High temperatures prevail deep inside the Earth’s surface, which can be used to produce energy with the help of geothermal power plants. Energy can also be obtained from plants in the form of biogas or fuel from sugarcane, which is used to run a number of cars in countries like Brazil.

Geothermal power plants convert the thermal energy of the Earth into electricity. This is truly worthwhile in those areas where the upper layers of the Earth have a temperature of more than 100°C, such as Iceland or several parts of Italy. Hot steam at a temperature of over 150°C can be used directly to drive the turbines. Other processes that use the heat of the Earth at a depth of several kilometres are still in the trial stage. In these processes, water is pressed at a high pressure in hot rocky layers, where it heats up in artificially created cracks. From there, it is pumped again to the Earth’s surface by means of a second drill. This heat can be used directly for heating or for generating electricity.