Energy from all these sources can show itself in different ways. We speak therefore of forms of energy. All these energy forms have one characteristic that is particularly interesting for our daily life: they can be transformed or converted from one form to another. For example, an internal combustion engine transforms chemical energy (the fuel) first into thermal energy and then into mechanical energy by means of the pistons that are part of the motor.
Radiant energy from the sun is at the heart of the phenomenon of photosynthesis (the process that helps plants develop and grow) and of the natural cycle of water (the evaporation phase)
.
Thermal energy is produced by solar
radiation or by the burning of combustible matter such as wood.
Mechanical energy gives rise to the
displacement of objects or solid bodies.
Chemical energy is stored in matter, in the molecules, which need a large input of energy for their creation. For example, explosives are concentrates of chemical energy.
The electrolysis of water produces chemical energy in the form of hydrogen and oxygen. Energy is present in a chemical form in the battery if a car.
Electrical energy corresponds to the displacement of electric currents in conducting bodies (in most cases metals). It exists in nature in the form of lightning, which, in fact, moves through the air. Or again, in the form of static electricity (electric charges fixed on a non-conducting body).
The conversion of one type of energy into another, for our advantage or convenience, is always accompanied by energy losses. Part of the energy transformed is dissipated into nature. For example, in a conventional internal combustion engine, almost 2/3 of the energy is "wasted" in heat. In an electric light bulb, energy losses in the form of heat are also important. When a car is driving along the road, part of the mechanical energy is not used for movement it is dissipated in friction (air resistance, friction of the tyres on the road). Researchers are constantly trying to find solutions to limit these energy losses and to increase the yield in each of these technologies. |