Energy: Definition, Types, and Examples

Introduction to Energy:

Our body gets the energy to play, think, and do work from the food we eat. Similarly, non-living things like cars, buses, airplanes, fans, TV, etc., also need energy to work but from different kinds of energy sources like petrol, diesel, or electricity. Energy exists in different forms.

Explanation:

Mechanical Energy:

One of the main types of energy is mechanical energy. It is the energy due to the motion or a special position of the object.

Kinetic Energy:

Kinetic energy is the energy due to motion. The amount of kinetic energy in a moving object depends on its mass and velocity. An object with greater mass or greater velocity has more kinetic energy.

Fig-1: Kinetic energy

Potential Energy:

Some objects that are not yet in motion also have a kind of energy. They have the potential to be in motion. In most cases, this ability comes from a special position or shape. An object has potential energy because of its position. For example, a rock at the top of a cliff or an apple on a tree has potential energy because it could fall. They fall because of the pull of gravity. Potential energy can be transferred into motion.

Fig-2: Potential energy

Another type of potential energy is related to the shape of an object. This energy is called elastic potential energy. This energy results when some objects are stretched or squeezed. For something to be elastic, it must have the ability to return to its shape.

Fig-3: Elastic potential energy

Chemical Energy:

A car and all vehicles can’t run without petrol or diesel. Computers, laptops, and some toys can’t work without batteries. We cannot even work without eating food. Batteries, petrol, diesel, coal, and wood are examples of stored chemical energy. Food is also a good example of stored chemical energy. This energy is released during digestion.

Chemical energy is the energy that is stored in the bonds of atoms and molecules. When a chemical reaction occurs, this energy is released.

Fig-4: Sources of chemical energy

Electrical Energy:

We cannot operate the fan, TV, light, fridge, and other electrical appliances without electricity. We cannot even charge our smartphones in case of a power cut. Electrical energy is a type of kinetic energy caused by moving electric charges. It is generated by tiny charged particles called electrons.

Fig-5: Source of electrical energy

Heat Energy:

The high temperature we feel coming from a fire, a room heater, and the burning of coal is an example of heat energy. This energy is also known as thermal energy. We know that matter is made up of molecules. When we raise the temperature of matter, the molecules vibrate and release heat energy.

Fig-6: Sources of heat energy

Light Energy:

We can’t see objects in the dark. Things are visible to us when they are illuminated or reflect light. Light energy is also known as radiant energy. Sun gives us a lot of light energy. In the absence of sunlight at night, we can’t see many things. Plants take light energy from the Sun and convert it into chemical energy (food), which helps them to grow; this is known as photosynthesis.

Sound Energy:

In our daily lives, we hear many sounds like the voices of many people, the clapping of hands, barking dogs, and the sound coming from the TV. Anything that we hear is carried by sound energy. The louder the sound is, the more sound energy it carries. Vibrating objects, strings of a guitar, the membrane of a drum, and the vocal cord of humans are the main sources of sound energy, which is transferred by the molecules present in the air. 

Fig-7: Sources of sound energy

Nuclear Energy:

All objects are made of atoms, and atoms are made of electrons, protons, and neutrons. The core of an atom is known as a nucleus. A nucleus is made of nucleons, which means protons and neutrons. Elections exist in an atom outside the nucleus.

Fig-8: An atom

Nuclear energy is released when atoms are joined together (nuclear fusion) or when an atom is split apart (nuclear fission).

Fig-9: Nuclear fusion and nuclear fission

Summary

• Energy is the ability to do work. It is of different types.
• Mechanical energy is the energy due to the motion or a special position of the object. It is of two types kinetic energy and potential energy.
• Chemical energy is the energy that is stored in the bonds of atoms and molecules. When a chemical reaction occurs, this energy is released.
• Electrical energy is generated by the motion of tiny charged particles called electrons.
• When we raise the temperature of matter the molecules vibrate and release heat energy.
• Light energy is also known as Radiant energy generated by luminous objects.
• Vibrating objects are the main source of sound energy.
• Nuclear energy is released when atoms are joined together (nuclear fusion) or when an atom is split apart (nuclear fission).