What Is Energy?

What is energy?

Well, simply put, energy is the capacity to do work. More precisely, energy is the ability to perform some action(s) or change(s) (e.g. kinetic energy, potential energy, thermal energy, luminous energy, etc.)

In most cases, the word “energy” has the same meaning in both science and everyday life. However, there are exceptions. For example, in physics, energy can be defined as the capacity to do work or the ability to perform an action. In chemistry and biology, the word “energy” often refers to the potential energy that a chemical or biological compound can possess.

Kinetic Energy vs. Potential Energy

Kinetic energy is the energy possessed by an object due to its motion. For example, if you throw a rock at a tree, the tree will react and then the motion of the rock will stop. This is because the rock has exerted a force on the tree, and thus the rock has transferred some of its motion to the tree (thus increasing the tree’s kinetic energy).

In contrast, potential energy is the energy that an object possesses due to its position or shape. As an example, if you throw the rock at a stable, flat surface, then the rock will remain in motion, however, it will not cause the surface to undulate because there is no potential energy between them (i.e. the rock has no effect on the surface’s shape).

Potential energy can be defined as the energy possessed by an object about to collide with another object. For example, when a comet strikes the Earth, the particles inside the comet are moving at high speeds towards the Earth. However, the vast majority of these particles have high amounts of energy (i.e. they are very hot), and thus they will not affect us on a human scale. In contrast, molecules that are on the surface of the comet will bounce around and eventually lose enough energy to fall below the human scale (i.e. they will not be heated to a sufficient degree).

Thermal Energy

Thermal energy is the form of energy which results from transferring thermal energy to other substances. Thermal energy can be defined as the energy possessed by a system as a result of its temperature and can in turn be expressed in several ways. For example, in SI units, thermal energy is commonly given in joules (J), calories (cal), or kilocalories (kcal). One calorie is defined as the energy it takes for an atom to change its state of motion.

The term “thermal energy” can sometimes be used interchangeably with the term “heat energy”, although there are some subtle differences between them. For example, the former is usually used to describe the energy within a system (e.g. a planet, star, or galaxy), while the latter can be used to describe the energy between objects (e.g. an electron and a positron, or atoms). Another difference is that thermal energy cannot be destroyed, while heat energy can be destroyed by exposure to air or water (at least in most cases).

Luminous Energy

Luminous energy is the form of energy that enables light to be emitted from a system. The term “luminous energy” can sometimes be used interchangeably with the term “radiant energy” and can in turn be expressed in several ways. For example, in SI units, luminous energy is commonly given in watt (W), candela (cd), or lux (lx). One watt is defined as the amount of energy needed to raise the temperature of one kilogram of water by one degree Celsius (1°C).

The term “luminous energy” can sometimes be used interchangeably with the term “radiant energy”, although there are some subtle differences between them. One such difference is that luminous energy can be converted into other forms of energy, whereas radiant energy cannot. For example, the energy within a luciferase enzyme is released in the form of light as it converts a luciferin substrate into a luciferase product. In most cases, luminous energy and radiant energy are used interchangeably, although they are not synonymous.

Polarization Energy

Polarization energy is the energy possessed by the orientation or vibration of electrons in atoms or molecules. This energy provides the capacity to cause electrons to become aligned in a certain direction, thus allowing for the development of an electric current. The orientation of molecules in a solid can also have an effect on the electrons in the molecule, which in turn provides the ability to conduct electricity. This is called the polarization effect.

The term “polarization energy” can sometimes be used interchangeably with the term “optical energy”, although there are some subtle differences between them. For example, the former is usually used to describe the energy within a system (e.g. a molecule), while the latter can be used to describe the energy between objects (e.g. an electron and a positron, or atoms). Another difference is that polarization energy is not independent from the source that provides molecules with their energy (i.e. they always have some optical energy associated with them).

Electric Energy

Electric energy is the form of energy that is associated with electricity and magnetic forces. This energy possesses the capacity to do work through the production of an electric current in a wire or the formation of magnetic fields around a permanent magnet. Electric energy can be defined in terms of several units. One common unit of measurement for electric energy is the joule (J), which is defined as an amount of energy equal to the work done by one newton (N) over a distance of one meter (m). N is a unit of force, making J an energy measure equal to the work done by one newton over a distance of one meter. Another unit of measurement for electric energy is the watt (W), which is defined as the energy needed to raise the temperature of one kilogram of water by one degree Celsius. One watt is equal to the work done by one newton over a distance of one meter. In some cases, however, electric energy can be measured in several different ways (e.g. in terms of amp-hours, volt-hours, etc.).

The term “electric energy” can sometimes be used interchangeably with the term “electrical energy”, although there are some subtle differences between them. For example, the former is usually used to describe the energy within a system (e.g. an atom or a molecule), while the latter can be used to describe the energy between objects (e.g. an electron and a positron, or atoms). Another difference is that electrical energy is a form of energy that can always exist, while electric energy can only exist when in the form of electric potential energy.

Radiant Energy

Radiant energy is the form of energy that results from electromagnetic radiation (e.g. light, infrared, radio, gamma rays, etc.). The term “radiant energy” can sometimes be used interchangeably with the term “photonic energy”, although there are some subtle differences between them. For example, a photonic energy packet can be absorbed by an object, while radiant energy cannot. When light is absorbed by an object, it releases a portion of its radiant energy as heat energy. In most cases, the term “radiant energy” can be used interchangeably with the term “photonic energy”, although it should not be used to describe the energy of other forms of radiation (e.g. gamma rays, radio waves, etc.).

Wave Energy

Wave energy is the form of energy that is associated with sound and light. This type of energy possesses the capacity to do work through the production of sound waves or light waves (e.g. radar waves, sonar waves, etc.). Wave energy can be defined in several ways, including in terms of several units. For example, one common unit of measurement for wave energy is the joule per second (J/s), which is defined as the energy contained in one wave per second. One joule per second is equal to the work done by one newton over a distance of one meter per second. If one compares this to the other forms of energy listed here, one will notice that wave energy is the least efficient at doing work (i.e. it requires the most energy to do the same amount of work as compared to any of the other forms of energy listed here).

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