You all might have read in your school textbooks that energy is the capacity to do work, usually when a force is applied. Considering energy is carried in the form of movement with no physical essence, this definition becomes quite vague. Therefore, we’ll take a deeper look at different kinds of energy in this article to understand it better. Broadly speaking, we can classify energy into two forms: kinetic energy and potential energy. In simple words, kinetic energy is concerned with moving objects, while potential energy is concerned with objects at rest.
Energy can be broadly classified into two types: potential and kinetic. Major forms of energy also include thermal (heat), chemical, nuclear, electrical, radiant (light), mechanical, and sound. Renewable energy sources like solar, wind, hydroelectric, geothermal, and biomass are increasingly important due to environmental concerns.
It’s also essential to know that one form of technology can be converted into other forms. We explained it in detail in our article about Energy Technology.
Energy can neither be created nor destroyed – only converted from one form of energy to another.
Law of Conservation of Energy
With that said, here are some of the different types of energy, organized into potential and kinetic.
1. Kinetic energy
Kinetic energy is the energy of an object due to its motion. It depends on both the mass and the speed of the object, with faster or more massive objects having more kinetic energy. The formula to calculate kinetic energy is KE = 1/2 mv^2, where m is the mass of the object and v is its velocity.
The object is said to have kinetic energy when it is in motion. So, the energy that an object has because of its motion is equal to the kinetic energy of that object. Along with the motion of the object, kinetic energy is also dependent on its mass. The following are the kinetic energy types:
1.1 – Thermal energy
The energy contained in the motion and vibration of the object’s molecules is its thermal energy. And, we use temperature to measure it. This means that if the temperature is high, then the object will be hotter, the reason being: more movements of particles of the object equal more thermal energy produced.
Since thermal energy comes from moving particles, it is classified into types of kinetic energy. An example of thermal energy is the cup with boiling water, where there are vibrating particles.
1.2 – Radiant energy
Radiant energy is the electromagnetic wave’s energy traveling through space. It can take two forms, which are visible and invisible waves. Light energy is visible waves, whereas radio waves are invisible waves. Here, the energy is carried in the oscillating electric and magnetic fields.
Also, it is measured by integrating radiant flux concerning time. An example of radiant energy is the Sun. Plants prepare their food, for example, by converting the electromagnetic energy in the sunlight into chemical energy.
1.3 – Electrical energy
Electrical energy is the form of energy caused by the movement of electrons, the negatively charged particles within atoms. When the electric charges, it’s the result of electrical energy created by the moving of electrons. Therefore, the movement of electrons is directly proportional to the quantity of energy. This means as the electric charges move faster, more electrical energy is carried.
Here, the electrons move when surrounding electric fields exert force. Considering the movement of electric charges, electrical energy is classified into a type of kinetic energy. An example of electrical energy is lightning, where the electricity is discharged into the atmosphere.
1.4 – Mechanical energy
The energy that is stored in moving objects is called mechanical energy or motion energy. Even though the object is moving, the mechanical energy is not just kinetic, but a sum of kinetic and potential energy. Let’s take the example of a wrecking ball to understand this better.
The wrecking ball has potential energy because of its weight, and when the force is applied to demolish the structures, it gains kinetic energy. A few other examples of mechanical energy are wind, swimming, and running.
1.5 – Sound energy
The sound energy comes from the vibrations moving through a substance. These substances can be solids, liquids, and gasses, where sound is transmitted as energy waves. For the transmission of vibrations, the atoms are used. But since there are no atoms in a vacuum, the sound waves cannot travel through it.
An example of sound energy is a musical instrument. When you play a musical instrument, the sound waves are generated, producing kinetic energy.
2. Potential energy
Potential energy is the energy an object possesses due to its position relative to other objects or its state. It represents the potential for the object to do work. For example, an object raised at a height has gravitational potential energy because it can do work when it falls.
Similarly, a stretched spring or rubber band (as shown in the image above) has elastic potential energy due to its deformation. The energy is “stored” and can be converted into kinetic energy.
The object is said to have potential energy based on its position in relation to other objects. The reason for it being called potential energy is that it has the potential to be converted to other energy forms. Here are several kinds of potential energy:
2.1 – Chemical energy
In the bonds of chemical compounds, the energy is stored, which is called chemical energy. It is classified into a form of potential energy, considering the energy is stored in the bonds of atoms. When chemical reactions take place, chemical energy is released, and byproducts, mostly heat, is produced. It is very important for existence and for this reason, you’ll find chemical energy in your everyday life.
An example of chemical energy is coal, where combustion converts the energy into light and heat. A few other examples of chemical energy are biomass, airbags, and natural gas.
2.2 – Nuclear energy
Nuclear energy is the energy released during nuclear reactions, such as fission or fusion. We have been taught that every object contains atoms, and these atoms are made up of neutrons, protons, and electrons. The nucleus is the core of the atom, from where the nuclear energy is released. Nuclear fusion and nuclear fission are two ways using which nuclear energy is produced.
In nuclear fusion, the nucleus of atoms, fuse. Whereas, in nuclear fission, they split into several parts. Using nuclear fission, nuclear power plants, harness nuclear energy to produce electricity. A few examples of nuclear energy uses are electricity, food treatments, nuclear medicine, and technology for space exploration.
2.3 – Gravitational energy
The energy possessed by the object depending on its position in a gravitational field is called gravitational energy. As the energy is stored in the object, it is classified into potential energy. To understand this better, let’s take an example. There are two objects, one is kept at the surface, while the other is held above the surface.
Here, the object kept at the surface has less gravitational energy compared to the one that is held above the surface. The reason is higher gravity due to moving against the center of the earth. A few other examples of gravitational energy are the pendulum, water stored in the dam, and the rollercoaster.
2.4 – Electric potential energy
The energy stored in the electric field is called electric potential energy. It is classified into potential energy as the energy is not used up until it is discharged. The SI unit of electric potential energy is the joule, and the formula to calculate it is E=Vq, where E is the electric potential energy, V is the voltage, and q is the charge. An example of electric potential energy is a capacitor, where an electrical field stores energy between two conducting plates.
Conclusion
In this discussion, we saw different types of energy along with examples. Energy is important to us, as it drives every form of movement. Right from chemical energy from the food that we eat to electrical energy for generating electricity, energy is everywhere.
So, we understand that energy is essential for everyday life. The sun, the primary energy source for living beings on Earth, provides warmth, helps in the process of photosynthesis, and drives the water cycle. All these things are necessary for survival. Apart from the sun, we use other energy sources in our daily lives, like fossil fuels (coal, oil, and natural gas), nuclear energy, hydroelectric energy, wind energy, and solar energy.
Fossil fuels like coal and oil are used to generate electricity. Nuclear power plants use nuclear energy to produce electricity. Hydroelectric dams harness the potential energy of water to produce electricity.
Nearly every process on our earth involves energy, which is why it is important to harness and use energy efficiently.