The nature of energy
John E. Beaver · Morgan & Claypool Publishers eBooks · 2018
Energy and colorJohn Beaver Chapter 1The nature of energy Energy has many forms.It appears that although energy can transform from one form to another, the total amount remains constant as stuff happens.This is called the conservation of energy, and it is one of the most important principles in physics.There is no good one-sentence definition of energy that does not raise more questions than it answers.As with other physical quantities, to be thorough we must use an operational definition, describing all of its properties in different circumstances.To do so would require a book of its own; here I give only a brief overview.There are many types of energy, some of which have familiar names; electrical energy, solar energy, chemical energy and nuclear energy, are examples.These different types of energy manifest themselves in different ways and under different circumstances (and so they have different names).But when it comes down to it, all types of energy can be described as some variety of four basic types, of which I give very brief descriptions here:• Kinetic energy-This is the energy due to an object's mass and motion, compared to some other frame of reference.• Gravitational energy-This is energy associated with the force of gravity.A glass gets nudged off the table and then falls to the floor and shatters.The energy to make the glass shatter came at the expense of a decrease in gravitational energy.• Electromagnetic energy-The energy associated with electric and magnetic forces is the basis for solar energy and chemical energy, among many other forms.Since light carries electromagnetic energy, it is of particular importance to photography.• Nuclear energy-This is the energy associated with the enormous forces at work in the nuclei of atoms.