What is Energy?- Definition, and Types of Energy

Energy is all around us. It’s responsible for making everything happen, whether you want to use any household appliance, take a walk through the park, drive your car across town, or do anything that involves movement or activity.

But what is energy? Though we are constantly surrounded by it, the nature of this elusive yet omnipresent force is often misunderstood or not thought about at all. 

What is Energy?

In Physics, energy is the capacity for doing work. It may exist in potential, kinetic, thermal, electrical, chemical, nuclear, or other forms.

Scientists define energy as the ability to do work. Modern civilization is possible because people have learned how to change energy from one form to another and then use it to do work.

People use energy to walk and bicycle, move cars along roads and boats through water, cook food on stoves, make ice in freezers, light our homes and offices, manufacture products, and send astronauts into space.

There are many different forms of energy, including

  • Heat
  • Light
  • Motion
  • Electrical
  • Chemical
  • Gravitational

These forms of energy can be grouped into two general types of energy for doing work:

  • Potential or stored energy
  • Kinetic or working energy

Energy can be converted from one form to another. For example, the food a person eats contains chemical energy, and a person’s body stores this energy until he or she uses it as kinetic energy during work or play. The stored chemical energy in coal or natural gas and the kinetic energy of water flowing in rivers can be converted to electrical energy, which in turn can be converted to light and heat.

Energy sources can be categorized as renewable or nonrenewable

There are many different sources of energy, which can be divided into two basic categories:

Renewable and nonrenewable energy sources can be used as primary energy sources to produce useful energy such as heat, or they can be used to produce secondary energy sources such as electricity and hydrogen.

Energy Formula:

Energy formulaEnergy = Power x Time
Kinetic energy formulaK.E. = 1/2 mv2
Potential energy formulaU=mgh
Gravitational potential energy formulaΔPEg = mgh
Conservation of energy formulaK1+U1 =K2+U2
Mechanical energy formula(Em=K+U) Mechanical energy = kinetic energy + potential energy
Elastic potential energy formulaElastic potential energy = force × displacement.
Internal energy formulaΔU  = Q + W
Spring potential energy formulaString potential energy = force × distance of displacement.
Electric potential energy formulaUE = k (q1q2/r)
Types of Energy

Why Is Energy Important?

Energy is essential for all life and all processes that occur across the entire universe. On Earth, the sun is the ultimate source of all energy that is available and used by people, animals, plants, and microorganisms.

This energy may come directly, such as in the form of photosynthesis, or indirectly, such as in the form of fossil fuels, which long ago trapped the energy of the sun that is released when burned.

Why Is Energy So Important in Our Lives?

Energy is so important in our daily lives because it is a basic human need. We use energy to not only heat our human-made structures but we use it to cool them as well. Energy is necessary for getting up out of bed, walking down the street, or even lifting your finger. It’s also necessary for an abundance of all types of modern conveniences, from light bulbs to appliances to vehicles.

Why Do We Need Energy?

We need energy for countless reasons. First and foremost, it is needed to simply stay alive. Energy is in everything that we eat, consume, or use. 

Energy fuels and regulates the body’s natural internal functions. It repairs cells and body tissue is used to build muscle and is necessary to maintain homeostasis and the harsher the environment, the more energy is needed to maintain this. 

Going a little deeper into the human body, energy is needed to produce enzymes, contract and move muscles, and carry electrical impulses between cells. In society, energy is needed for everything from driving to watching television to keeping homes and businesses lit with artificial light.  

Energy is needed for almost anything and everything in life. Even when we are not paying attention to it, energy is present, regulating body functions while at rest or powering your household appliances even if they are turned off. 

Where Does Our Energy Come From? 

Energy is all around us. Ultimately, nearly all energy comes from the sun, where nuclear fusion reactions create massive amounts of energy as atoms are fused in the core and released out toward Earth. But the energy we use in everyday life comes from a variety of sources that have captured and stored this initial energy. 

Where Can Energy Be Found?

We can find available energy all over the world. When we eat food, we are consuming a form of stored chemical energy. If we are eating plants, we are consuming a primary source of energy, as these organisms use photosynthesis to capture the sun’s energy, which is then stored in their cells. If we are eating meat, we are consuming secondary sources of energy, usually from animals that have eaten primary producers. 

For societal and industrial uses, energy can be found stored in fossil fuels, in the atomic bonds of nuclear particles, or powered by the Earth’s processes such as wind power, hydropower, or geothermal energy. These are also considered primary energy sources because we are extracting energy directly from them. 

Where Do Most of Our Electrical Energy Come From? 

When it comes to our energy supply for daily life, the majority comes mainly from fossil fuels, nuclear power, and renewable energy sources like solar and biomass. Electricity, or electrical energy, is generated using these forms, mostly in large-scale grid generation but also in small-scale and off-grid production. Electricity falls into its own category as it’s an energy carrier, not a primary source. 

Fossil fuels used for electricity generation include coal, oil, and natural gas. Nuclear energy is unique as it is a nonrenewable form of electricity generation that does not produce carbon dioxide emissions. Nuclear power plants use fission, or the act of splitting atoms, to release high amounts of energy that are then used to boil water. The resulting steam turns into a turbine that generates electricity.  

Renewable energy uses forms of energy that are much more readily available than fossil fuels, often taking energy from processes that are dictated by the sun (and in the case of solar energy, taking energy directly from the sun). Wind energy, hydropower, and geothermal all use Earth’s processes to spin turbines for electricity generation. 

Types of Energy

Types of energy can be categorized into two broad categories – kinetic energy (the energy of moving objects) and potential energy (energy that is stored). These are the two basic forms of energy.

The different types of energy are as follows: Electrical Energy, Chemical Energy, Mechanical Energy, Thermal Energy, and Nuclear Energy.

Kinetic Energy

All moving objects have kinetic energy. Kinetic energy is the energy an object has because of its motion. It can define as the work needed to accelerate a body from rest to its current velocity. Kinetic energy depends on the mass of the object.

When the velocity or the mass of a body increases, the kinetic energy also increases. The kinetic energy can be either zero or positive. Some examples of kinetic energy are moving cars, moving the ball, a river flowing, an athlete running, and a satellite revolving in an orbit.

1. Radiant Energy

Radiant energy is electromagnetic energy that travels in transverse waves. Electromagnetic energy is a type of energy in which energy is emitted through electrical or magnetic waves traveling through space.

These waves do not require a medium and travel through empty space at the speed of light. It has vibrations of both electricity and magnetism. Some examples of electromagnetic waves are X-rays, and microwaves. Radio, gamma rays, and ultraviolet rays are examples of electromagnetic waves.

2. Thermal Energy

Thermal energy is also known as Heat energy. This is a type of energy in which the object gets energy due to the movement of the molecules within the object. As the movement of these molecules becomes faster, more heat is produced.

Heat energy on Earth is from the sun above. This energy can transfer only by convection, conduction, and radiation. It is difficult to convert heat energy into other forms. Some of examples of heat are gas stove burners, and a hot cup of coffee and when u rub your hand together, heat energy is produced.

3. Motion Energy

Motion energy is energy stored in the movement of objects. The faster they move; the more energy is stored. It takes energy to make an object move, and energy is released when an object slows down. The wind is an example of motion energy.

A dramatic example of motion energy is a car crash—a car comes to a total stop and releases all of its motion energy at once in an uncontrolled instant.

4. Sound Energy

Sound energy is a type of energy in which associated with matter vibrations. Sound energy needs a medium to travel and produces low levels of energy. Due to this property of sound, there is no sound in space. 

The measurement of these waves depends upon their intensity and pressure. Sound travels fastest through a liquid. The sound of vehicles, wind chimes, laughing, crying, water falling, boiling, whistles, guitars all are examples of sound energy.

5. Electric Energy

Electric energy is a type of energy due to the movement of electric charge and can be commonly called electricity. The origin is from electromagnetic forces. When this electrical energy flows, a little bit of heat energy is generated. Electric heaters, appliances, lights, fans, television, and all use electrical energy.

Potential Energy

Potential energy is a type of energy possessed by an object due to its virtue or position. In simpler terms, potential energy is something that is present but does not do any work. It is stored energy and can convert to kinetic energy.

Some examples of potential energy are holding a pen up, a car on a hilltop, a stretched rubber band, a glass of milk, and fruit hanging from a tree.

1. Chemical Energy

Chemical energy is a type of energy stored in chemical compounds and released during a chemical reaction. In most of these reactions, heat energy is the byproduct. Chemical energy is the most common form of energy.

It comes in different forms and can constantly change form. The food that we eat, all battery-powered devices, and the combustion of oil, fuel, gas, and electricity are some examples of chemical energy.

2. Mechanical Energy

Mechanical energy is the sum of the kinetic energy, or energy of motion, and the potential energy, or energy stored in a system by reason of the position of its parts.

Mechanical energy is constant in a system that has only gravitational forces or in an otherwise idealized system that is, one lacking dissipative force, such as friction and air resistance, or one in which such forces can be reasonably neglected.

3. Nuclear Energy

Nuclear energy is a type of energy inside the atom in the nucleus. Each object around us is made up of an atom. There is a lot of energy in these atoms. On certain grounds, these atoms release energy that can be harmful and useful to mankind.

This energy can be used to generate electricity, boil water to create steam and even explode a nuclear bomb.

4. Atomic Energy

Atomic Energy is produced when you split atoms. A tremendous amount of energy is released when this happens. Atomic bombs, nuclear power plants, nuclear submarines, and the sun are some examples of Atomic Energy.

5. Gravitational Energy

Gravitational energy is a type of energy possessed by an object when it is moved against gravity. This is mainly caused due to the pull of gravity. The higher the object, the higher the gravitational energy.

The force of gravity of an object depends upon its mass of the object. Some examples of gravitational energy are water stored in a dam, rocks at the top of a hill, and a parachute.

6. Solar Energy

Solar energy is the energy that is received from the sun. It is the most abundant and the most renewable form of energy. If the entire population efficiently use this solar energy for all purposes no other form of energy needs to be utilized.

It is a free source of heat and light energy. Solar panels, cells, torches, lights, fans, solar farms, and solar stations are some of the variations that use the sun as their medium.

7. Magnetic Energy

Magnetic energy is a type of energy stored in the magnetic fields in magnets. All magnets are examples of magnetic energy.

8. Surface Energy

Surface energy is a type of energy that is present by virtue of existence. This type of energy is present in a stretched rubber band, stagnant water, etc. in simple terms when 2 liquids come in contact with each other, surface tension is created.

This is surface energy. Usually, in solids, surface energy combines with elastic energy. If an insect floats on the water then it is because of the surface energy.

9. Wind Energy

Wind energy is the energy of the winds. This is a green, renewable, and affordable source of energy that is utilized for a long period of time. Wind energy is utilized in the form of windmills and turbines which convert the kinetic energy of the wind into mechanical energy and further into electric energy.

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