ENERGY & ITS TYPES
What is Energy?
The word 'energy' was invented less than 200 years ago by an English scientist named Thomas Young. He used it for the first time in 1807.
Energy is something that makes it possible to do work, and work is something that takes effort. Thomas Young made up the word "energy" from a Greek expression that means "work inside". Energy is something that has "work inside it" One can use that energy and get work out of it.
TYPES OF ENERGY
In ancient times, muscle power was used in the form of energy. That was the time people did not know much about energy. Animals also used muscle power to do work. People also invented few simple tools so that muscle energy could be used more efficiently. Animals were put to use for these simple tools.
Energy from Fire
Fire is used from ancient times for various purposes starting from warming their houses to smelting ores. Most of the energy from the fire is heat energy that is released when a fuel is burnt. Energy from fire also gives out light and sound. Firstly, wood was used as fuel and after some time, coal was used.
Energy from Wind and Water
Early civilizations used ‘mechanical energy’ to do work which could be obtained from wind or water. Wind and water flow are the most visible natural energy flow, but the energy is originally from the sun.
Potential energy is stored whenever something moves in the opposite direction of the force acting on it. There are many forms of potential energy and many forms of energy that it can become. But, the total amount of energy always remains the same.
Every moving object has ‘kinetic energy’.
The more the mass of the object, the more is the kinetic energy for the same energy. Scientists noticed that this energy seemed to be “conserved”. For example – A moving ball could transfer its energy to a stationary one. However, when a moving object hits a soft object, it is obvious that the energy is not conserved because the object seems to absorb the movement.
A series of experiments involving friction demonstrated that heat could be generated from muscle energy. Heat was finally shown to be a form of energy. The study of heat energy is called Thermodynamics. It is now common knowledge that heat is simply kinetic energy of the countless moving atoms and molecules of matter.
When steam condenses, or turns back into water, it suddenly occupies a much smaller space than before. Before steam engines, flooding in coalmines had been controlled using pumps driven by animals or water wheels.
Atoms consist of tiny nuclei surrounded by electrons. The nucleus was found to be made up of tightly packed particles, which were named protons and neutrons. Electrons are held in the atom by electromagnetism, but the forces that hold the nucleus together are far greater. Those forces are the key to nuclear power. Fission and Fusion are the two main ways by which this energy can be released. In each case a reaction occurs in the nuclei of atoms, and the matter left after the reaction has a little less mass than before. The “lost” mass is changed into energy, some of which is released as high-energy electromagnetic radiation. The rest becomes heat, which can be used to destroy things in nuclear weapons or the generate electricity in nuclear reactors.
Kinetic energy and potential energy are together known as ‘Mechanical energy’. That is because in machines there are always moving parts that move faster and slower, higher and lower. In machines, kinetic energy is often turning into potential energy and back again. For example – For a pendulum, we can say that the kinetic energy and the potential energy are always changing in amounts. The total amount of mechanical energy is however the same. When the total quantity of something doesn’t change as the objects are shifting and moving about, that something is said to be conserved. In a pendulum, there is conservation of mechanical energy.