Energy: Introduction and Types

Show/Hide Page Index


In physics, energy is defined as a property of objects which can be transferred from one object to another object or converted into different forms of energy. Energy is the capacity to do work, generating heat and emitting light.

Heat is the ability to change the temperature of an object or phase of a substance. For example, heat changes from ice into water or water into water vapor. Heat is part of the definition of energy. Another part of the definition of energy is radiation, which is the light and energy emitted in the form of waves traveling at the speed of light (3 × 108 m/s).

Energy is measured in calorie, erg, and joule units. One kilo-calorie is the amount of heat energy required to raise the temperature of 1 kg of water from 14.5°C to 15.5°C temperature.

There are different types of energy forms, they include nuclear energy, electrical energy, thermal energy, chemical energy and radiant energy. In addition, gravitational potential energy and kinetic energy combine to produce mechanical energy.

The nuclear reaction produces heat by fission on nuclei, which is generated by heat engines. A nuclear reaction is the world’s largest source of emission-free energy. There are two processes in a nuclear reaction.

  1. In the fission process, the nuclei of uranium or plutonium atoms split to release energy.
  2. In the fusion process, energy is released when small nuclei combine with each other.

Nuclear energy is used to heat steam engines. A nuclear power plant is a steam engine using uranium as its fuel and it suffers from low efficiency.

Electrical energy powers most industries and houses. Some electrical equipment like flashlights and game toys use electricity that is stored in batteries in the form of chemical energy. Other electronic devices use electricity that comes from an electrical plug in a wall socket. Electricity is the conduction of energy from one place to another place. Electricity is the flow of energy. Atoms have electrons circling them, some being loosely attached. When electrons move among the atoms of matter, a current of electricity is generated.

Thermal energy is kinetic and potential energy, but it is associated with the random motion of atoms in an object. The kinetic and potential energy associated with this random microscopic motion is called thermal energy. A great amount of thermal energy is stored in the world’s oceans. Every day ocean water absorbs enough heat from the sun.

Chemical energy is a form of energy that comes from chemical reactions, in which the chemical reaction is a process of oxidation. Potential energy is released when a chemical reaction occurs in the form of chemical energy. A car battery is a good example of chemical energy because the chemical reaction produces voltage and current to start the car engine. When a plant goes through a process of photosynthesis, the plant is left with more chemical energy than water and carbon dioxide. Chemical energy is used in science laboratories to manufacture medicines and to produce power from gas.

Radiant energy exists in a range of wavelengths that extends from radio waves that may be in the thousands of meters long wavelength to gamma rays with wavelengths as short as a million-millionth of a meter. Radiant energy is converted to chemical energy through the photosynthesis process.

Potential energy exists whenever an object which has mass has a position within a force field. The potential energy of an object in this case is given by the equation P.E = mgh, where ‘P.E’ is potential energy, ‘m’ is the mass of the object, ‘g’ is the gravitational acceleration, and ‘h’ is the height of the object goes.

Kinetic energy is the energy of motion. An object in motion, whether it be in a vertical or horizontal direction motion, has kinetic energy. There are different forms of kinetic energy vibrational, which is the energy due to vibrational motion, rotational, which is the energy due to rotational motion and transnational, which is the energy due to motion from one location to the other. The equation for kinetic energy is given by ½ mv2, where ‘m’ is the mass of the object and ‘v’ is the velocity. The kinetic energy of an object is directly proportional to the mass of the object and the square of the object’s velocity.

Spread the Knowledge

'ME Mechanical' is an online portal for mechanical engineers and engineering students. Published hundreds of articles on various engineering topics. Visit our about section to know more.

Leave a Reply

Your email address will not be published. Required fields are marked *

This site uses Akismet to reduce spam. Learn how your comment data is processed.