Energy-Origin of everything
What is energy?All creation myths account for energy. Whether the universe emerged from nothingness, or the universe repeats in a cycle of creation, evolution, and destruction or the universe exists from infinity towards infinity or the universe spirited into existence by divine intervention, all myths focus around energy. For instance, in Hinduism, the word energy directly translates into sakthi, which means goddess. Parasakthi is the ultimate energy who is held as the supreme force of creation and governance of the universe. My purpose here is not to explore many ways as to the creation of the universe or the origin of energy, rather my purpose is to impress upon the fundamental nature of energy.
Energy is everything. All matter is energy. (We will defer the discussion about non-matter concepts such as soul, spirit, ghosts, mind etc) In fact, according to Einstein E=mc2, where E is energy, m is mass (of the object), and c is the speed of light constant. Energy is physical property of an object-the mass, and its state or the speed at which it travels.
Energy is an abstract concept. Although, we say energy is measured in terms of Joules, we can not measure energy absolutely. For instance, the question: how much energy does 1Kg steel has is ambiguous. Perhaps, we could say if the 1Kg of steel travels at the speed of light, it has energy equal to E=1(3x108) joules. Then, what about the steel's potential energy! I am unclear when I discuss energy at this level of abstraction, thus I delay the discussion for another time.
What is the conventional definition of energy?
The conventional theory about energy is as follows: energy is the capacity to do work. Work is moving or displacing an object. When we say an object has energy, the statement refers to "a state or condition" about the object that can be measured.
Total energy of an object is the sum of three forms of energy: kinetic energy, potential energy and internal energy. The kinetic energy depends on the speed of the object. Potential energy is due to the object being in a field of force. The internal energy is associated with energy within the atomic structure.
Do we use energy to do work?
Conventionally speaking we use force to do work. And energy indicates the capacity to do work by an object or matter.
Consider the analogy. A person need to be healthy in order to play sports. But playing sports can not be equated with his state of health. Health is a state of the person, while playing is an activity. Similarly, an object's energy is a sate, doing work is an activity.
Nevertheless, the sate or the energy of the object does change as a result of doing work.
Technically, work equals energy expended, both have the same units!
How exactly are energy and work related?
"Work is the measure of a quantity that is capable of accomplishing Macroscopic Motion of a System due to the action of a Force over a Distance."
In scientific literature, work is defined in such as manner that is not often intuitive. A person may exert force on the object, using up some of his energy, but if she/he is not able to move the object in a macroscopic motion, then the work done is considered zero.
How do you create energy?
You can not create energy. Energy can only be transferred from one form to another. According to the "law of conservation of energy" the amount of energy before and after an event or a chemical reaction is always same. The law implies that the energy within the universe is constant, but the statement is arguable.
Is not the sun a permanent source of energy?
Sun is a source of energy for earth. The earth looses energy into space in such a relation that earth does not continuously absorb suns heat. Still, the scientists hold that the energy within the universe to be constant.
If energy is not created or used up why do we pay electric bills?
Energy can not be created or destroyed. The statement is true for practical purposes. Energy is converted from other forms such as
The electromagnetic energy is easier to transmit, and manipulate than other forms of energy. The cost we pay to the electric company is mainly for the conversion, and transmission of electromagnetic energy, which we then convert to other forms such as light or heat through the use of electrical appliances. Also, electrical signals are used to represent information, and thus important.
Energy is required to do work. But, force is used to do work! How is energy and force related? Is force and energy the same thing?
Energy and force are ambiguously defined. Physicists still argue over the definitions. Although force (along the displacement) times displacement equals work, and work and energy have the same units, force and energy are not defined to be exactly the same thing.
"Energy is force exerted through a distance"
Lets list the ways energy and force are different:
| Force is a vector quantity. | Energy is a scalar quantity |
| Force is applied to or by an object. | Energy is transferred to or from an object. |
| Force is exerted when energy is transferred from one force to another. | ??? |
What exactly is force?
In common use, we say we are using force when we are pushing or pulling something. We say that we are using force when we move an object or act on a moving object to increase or decrease its speed. We say we apply force when we store energy in a spring.
As discussed above, force is the means by which energy can be converted from one form to another. (I am still not clear about my last statement.)
Is force a material thing?
No. But a property of material things.
Is there only one kind of force?
There are four kinds of forces:
Is the nature of above forces the same?
As far as I understand, force is a property of matter. Each force is significant in its own field of influence. (When scientist created the atomic bomb, they are said to have harnessed the internal energy of atoms.) Thus, we can not say gravitational force is always the strongest on an object, or electromagnetic force is the strongest. The strength depends on what object we are considering and under what conditions.
In terms of the nature of force, consider the analogy of pressure acting on a wall in Figure 1. There is wind pressure and water pressure, but pressure none the less. I consider forces acting on an object in a similar way.
What is gravitational force?
Objects near the earth are attracted towards the earth due to gravitational force between the earth and the object. The earth and the object exert equal amount of force between each other. The gravitational force is due to mass of the objects involved. (This is a conventional explanation, I will explore in detail at a different time.)
What are weak forces?
What is electromagnetic force?
What are strong forces?
Do you recall the atomic theory of matter? It states that matter is composed of atoms. Atoms are made up of neutrons and protons, which form its nucleus, and electrons that buzz around. Also recall that like forces repel. Then how do you suppose that the protons are bundled up in the nucleus? The standard answer is that a force, a strong force is keeping the protons and neutrons together. The theory is more involved but we'll stop there.
Would you describe the atomic theory of matter?
(Continuity question)