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# Concept of energy

Energy is regarded as a significant property of matter, which has the potential of being converted into radiation, heat, or work. This indicates that various biological, physical, and chemical processes rely on energy in order to accomplish their goals. Further, the use of energy demands the conversion of energy from one form to another. As such, it is difficult to destroy or create energy, but the transformation of energy from one form to another form is possible through the adoption of various physical processes. The transformation of energy takes into consideration of the use of energy in the form of work, radiation, and heat. This aids in application of energy to various processes and life activities. ## Purpose

The concept of energy is useful since it aids in describing various processes, which occur in the universe. These include the various energy transformations, which are present in the natural and man made world. These energy forms include electromagnetic energy, chemical energy, kinetic energy, electrical energy, elastic energy, heat energy, gravitational energy, mass energy, and nuclear energy. As such, conservation of energy takes place during the transformation process. However, energy is transformed from one form to another form.

## Energy Transformation

Physical processes are comprised of “initial states”, which transform the processes into “final states”. As such, the transformation process is characterized by a change in energy (Ei). The change in energy is influenced by a system’s surroundings. Equation 1 depicts a typical energy transformation process.

∆ Ei = Efinal, i – Einitial, i        …………………….…………………………1

Further, since the transformation process of energy involves the conservation of energy, the sum of all energy changes is zero. Equation 2 illustrates the equation for conservation of energy.

∆E+ ∆E2 + … = i= 0 ……………………….………………….2

As equation 1 and 2 indicate, there are two points, which are significant in the concept of energy. The first point is that, during energy transformation process, the change in energy is vital. As such, the final and initial energy states are not significant in the energy concept. Further, physical laws play a crucial part in determining how energy changes occur in the physical process of energy transformation. The other point is that all the ways in which energy may change should be accounted for in an energy transformation process. Nevertheless, in all changes of energy, energy has to be conserved. Equation 3 depicts an energy conservation equation.

∆Esystem + ∆Esurroundings = 0 ……………………………….……….3

## Units of Energy

According to Moran et al., the unit of work is force times distance. However, various energy forms have independent units of energy. For example, the units of potential and kinetic energy are force times distance. Nevertheless, the SI unit of energy is Newton-Meter (Nm), which is referred to as a joule. As such, the units of energy adopted depend on the application of energy form.

## The Law of Energy Conservation

According to Kreith et al., the first law of thermodynamics states that “Energy cannot be created or destroyed but can be transformed from one form to another”. This first law of thermodynamics is also regarded as the law of energy conservation. This law claims that the total amount of energy and work into the system is equal to the total amount of energy and work out of the system. This indicates that, in an isolated system, the total amount of energy remains constant.

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