All around us, including humans, energy is one of the common things that occur. Energy is vast because it takes place in almost every application, starting with ourselves. That is the energy we use in surviving, the energy we get from food.
There is a different source of energy today that allows human civilization to function. Most of the energy comes from fossil fuels, nuclear fuel, or renewable energy, although these energies are used to produce other forms of energy such as mechanical energy, electrical energy, etc.
This is why the study of energy is very necessary to learn and understand. Well, in this reading, we’ll explore what energy is, its applications, importance, examples, types, and forms of energy. We’ll also explore the unit of measure, transformation, and conservation of energy.
Let’s get started!
What Is Energy?
Energy can be defined as the ability of a physical system to perform work; that is, a system possesses energy when it has the ability to do work. In other words, energy is transferred or transformed whenever work is done. However, the exitance of energy in a system does not mean it’s necessarily available to do work.
In physics, energy is known to be the quantitative property that must be transferred to a body or physical system to perform work on the body or to heat it.
Energy is a conserved quantity, which brought us to the law of conservation of energy. This law states that energy can be converted in form, but can neither be created nor destroyed.
All types of energy are of two forms, which include the kinetic energy of a moving object and potential energy stored by an object’s position in a force field. The unit of measurement of energy is called joule.
I want you to understand energy as the following:
- a scalar quantity
- abstract and cannot always be perceived
- given meaning through calculation
- a central concept in science
What are the Uses of Energy?
Energy is used in our daily lives and comes from kinetic and potential energy. The energy forms of kinetic energy include mechanical energy used in automobiles and agricultural equipment.
Also, electrical energy is used to generate electricity in our homes and offices, thermal energy is used to produce heat, and sound energy is used in speakers and mics.
While potential energy is of great use, it includes chemical energy used for food preservation and drugs; electric energy can be seen in television before it is turned on; elastic energy used in springs and rubber bands; and gravitational energy used to get free movement down from a hill.
There are three basic uses and importance energy offers to humans, which include residential uses, commercial uses, and transportation uses.
Residential Uses of Energy
This is the most common way energy is consumed, because they serve our daily home activities such as watching television, heating and lighting the home, taking a shower, washing clothes, working from home on your computer or laptop, running appliances, cooking, etc.
Almost forty percent of total energy use globally is for residential purposes. Although it is the common way energy is also wasted. This is a result of the lack of education offered to the public over how to conserve energy use daily.
Commercial Uses
The commercial uses include heating, cooling, and lighting of commercial buildings and spaces, and power used by organizations and businesses. The use of energy here is more or less similar to the use in the industrial space, save for personal uses.
Transportation Uses
This side of energy consumption is wholly dependent on energy, that is, over seventy percent of petroleum is used in the transport sector. The transport sector includes all vehicles, from personal cars to trucks to buses and motorcycles. It also includes aircraft, ships, trains, and pipelines.
The following are the common importance of energy around us:
- Energy powers communications, transportations, computers cutting-edge medical equipment, etc.
- Energy supports economic and social progress, building a better quality of life.
- Reliable and affordable energy allows the products and services that enrich and extend life.
- Energy can improve and even save lives.
- It supports expanded industry, modern agriculture, increased trade, and improved transportation.
- It creates better lives and reduces poverty.
Related: What is Fluid Mechanics? its Types and Working Principle
Forms and Types of Energy
There are different forms of energy that exist; they are all categorized into kinetic or potential. The energy associated with motion is known as kinetic energy, while potential energy is an energy associated with position, but it is not “stored energy.”.
Kinetic Energy
Kinetic energy is the energy of motion, that is, atoms and their components are in motion. With this, we can say all matter possesses kinetic energy, even on a larger scale. The common formula for kinetic energy is for a moving mass:
KE = 1/2 mv2
KE is kinetic energy, m is mass, and v is velocity. A typical unit for kinetic energy is the joule.
- kinetic energy — motion
- mechanical energy — motion of macroscopic systems
- machines
- wind energy
- wave energy
- sound (sonic, acoustic) energy
- thermal energy — motion of particles of matter
- geothermal energy
- electric energy — motion of charges
- household current
- lightning
- electromagnetic radiation —disruption of electric and magnetic fields (classical physics) or the motion of photons (quantum physics)
- radio, microwaves, infrared, light, ultraviolet, x-rays, gamma rays, solar energy
- mechanical energy — motion of macroscopic systems
Potential Energy
These forms of energy are energy that matter gains from its arrangement or position. The object has the potential to do work. A book on a table, a sled at the top of a hit, and a pendulum at the top of its swing are excellent examples of potential energy.
The common equations for potential energy that can be used to determine the energy of an object with respect to its height above a base are:
E = mgh where:
PE is potential energy, m is mass, g is the acceleration due to gravity, and h is height. However, the common unit of potential energy is the joule (J). This is because potential energy reflects the position of an object; it can have a negative sign. Either positive or negative still depends on work done by the system or on the system.
- potential energy — position or arrangement
- gravitational potential energy
- roller coaster
- waterwheel
- hydroelectric power
- electromagnetic potential energy
- electric potential energy
- magnetic potential energy
- chemical potential energy
- elastic potential energy
- strong nuclear potential energy
- nuclear power
- nuclear weapons
- weak nuclear potential energy, radioactive decay
- gravitational potential energy
Heat, kinetic or mechanical energy, light, potential energy, and electrical energy are the various forms in which energy exists.
Mechanical energy
Mechanical energy is the sum of kinetic energy and potential energy. It is the result of the movement or location of an object. A good example of mechanical energy includes a flowing river, a person running, or a wind blow.
The energy is stored in objects; that is, as the object moves faster, the more energy is stored. These types of energy are also known as motion energy.
Thermal energy
Thermal energy is the reflected temperature difference between two systems. It is created from the vibration of atoms and molecules within substances. The faster they move, the more energy they possess and the hotter they become.
An example of thermal energy is a cup of hot coffee. You generate thermal energy with respect to your environment. These types of energy are also called heat energy.
Nuclear energy
Nuclear energy is the energy resulting from changes in the atomic nuclei or from nuclear reactions. The energy is stored in the nucleus of atoms, and it’s released when the nuclei are combined (fusion) or split apart (fission).
In nuclear power plants, the nuclei of uranium atoms are split to produce electricity, which is one good example of this energy.
Chemical energy
This energy results from chemical reactions between atoms or molecules; it is stored in bonds of atoms and molecules. This is the energy that holds the particles together. Chemical energy is of different types, which include electrochemical energy and chemiluminescence.
A useful example of chemical energy is an electrochemical cell or battery. Also, stored chemical energy is found in biomass, natural gas, food, and petroleum.
Electromagnetic energy
These are energy from light or electromagnetic waves. It is a type of kinetic energy that travels in waves. examples of these types of energy are any form of light, including parts of the spectrum we can’t see.
Radio, gamma rays, x-rays, microwaves, and ultraviolet light are examples of electromagnetic energy. This energy is also called light energy or radiant energy.
Sonic energy
This energy is obtained from sound waves. Sound energy is the movement of energy through substances, either through the air or another medium. Sound energy is produced when a force makes an object or substance vibrate.
There is usually much less energy in sound than any other form of energy. Examples are sonic boom, a song played on a stereo, you talking or singing.
Gravitational energy
This energy involves the attraction between two objects based on their mass. It is a form of potential energy and can serve as a basis for mechanical energy. Also, as kinetic energy of the moon in orbit around the earth.
The energy is associated with gravity or gravitational force, which is the energy held by an object when it is in a high position compared to a lower position.
Ionization energy
Ionization energy is a form of energy that binds electrons to the nucleus of its atom, ion, or molecule. For instance, the first ionization energy of an atom is the energy needed to remove one electron completely.
The second ionization energy is energy to remove a second electron and is greater than that needed to eliminate the first electron.
Light energy
Light energy is a form of electromagnetic radiation, consisting of photons that are produced when an object’s atoms heat up. The light travels in waves and is the only form of energy visible to the human eye. Finally,
Elastic energy
This is a form of potential energy that is stored in an elastic object, such as a coiled spring or a stretched elastic band. Elastic energy is stored in objects when a force causes them to be stretched or squashed.
What are the examples of energy?
- Heat is also known as thermal energy from the movement of atoms or molecules. It may be considered as energy relating to temperature.
- Kinetic energy is the energy of motion. A good example is a swinging pendulum bob.
- Potential energy is due to an object’s position. A good example is a ball sitting on a table with respect to the floor because gravity acts upon it.
- Mechanical energy is the sum of kinetic energy and the potential energy of a body.
- Light energy is available as photons.
- Electrical energy is energy from the movement of charged particles like protons, electrons, or ions.
- Magnetic energy is a form of energy obtained from a magnetic field.
- Chemical energy is released or obtained from chemical reactions, produced by breaking or forming chemical bonds between atoms and molecules.
- Nuclear energy is energy from interactions with the protons and neutrons of an atom. A good example is energy released by fission and fusion.
Units of Energy
The SI unit of energy is the joule (J) or newton-meter (N * m). The joule is also the SI unit of work. It is named after James Prescott Joule who independently discovered the mechanical equivalent in a series of experiments. The SI unit of energy rate (energy per unit time) is the watt, which is a joule per second.
Energy Transformation
There are various forms of energy transformation, which may occur at various efficiencies. The items that transform between these forms are known as transducers. A useful example of transducers includes a battery, whose transformation takes place from chemical energy to electrical energy.
A dam transforms from gravitational potential energy to kinetic energy of moving water and also blades of a turbine. Also, electrical energy through an electric generator or a heat engine.
Good examples of energy transformation include electric energy generation from energy through a steam turbine or lifting an object against gravity using electrical energy driving a crane motor.
The lifting against gravity does mechanical work on the object and stores gravitational potential energy in the object. The falling of the object to the ground allows mechanical work to be performed by gravity on the object.
This transforms the potential energy in the gravitational field to the kinetic energy released as heat on impact with the ground.
Another good example of energy is the sun, which transforms nuclear potential energy into other forms of energy. Although its total mass does not decrease since it still contains the same total energy even when it occurs in different forms.
However, its mass will decrease when the energy escapes out to its surroundings, largely as radiant energy.
An experiment has shown that there are limits to how heat can efficiently be converted into work in a cyclic process, e.g., in a heat engine. Carnot’s theorem and the second law of thermodynamics highly elucidate that.
Despite that, some energy transformations are highly efficient, even though there are some factors to be considered. Entropy helps us determine the direction of transformations in energy (what kind of energy is transformed and to what type)
Conservation of Energy
Just as earlier stated, the law of conservation of energy says energy can neither be created nor destroyed. The first law of thermodynamics states that a closed system’s energy is constant unless energy is transferred in or out by work or heat and that no energy is lost in the transfer.
This is to say, the total inflow of energy into a system must equal the total outflow of energy from the system plus the change in the energy contained within the system.
The total energy of a system will always remain constant if someone measures or calculates the total energy of a system of particles whose interactions do not depend on time.
A good example is when two billiard balls collide, which may come to rest, with the resulting energy becoming sound and maybe little heat at the point of collision. There is kinetic energy when the balls are in motion.
They have potential energy, whether in motion or stationary, because they are on a table above the ground.
One of the common forms of energy transformation is the conversion of heat into work in a reversible isothermal expansion of an ideal gas. The second law of thermodynamics states that the system working always loses some energy as waste heat.
This creates a limit to the amount of heat energy that can do work in a cyclic process. Although mechanical and other forms of energy can be transformed in the other direction into thermal energy without such limitations.
The total energy of a system can be calculated by adding up all forms of energy in the system.
Conclusion
Energy is the ability of a physical system to perform work; that is, a system possesses energy when it has the ability to do work. In other words, energy is transferred or transformed whenever work is done.
That is all for this post, where the definition, use, importance, examples, types, and forms of energy is being discussed. You also learned the unit of measure, transformation, and conservation of energy.