In a revolutionary scientific work discovered by Albert Einstein in 1905, E = mc2 introduced, where: E is energy, m is mass, and c is the speed of light in a vacuum. Since then, E = mc2 has become one of the most recognized equations in the world. In fact, people without a background in physics have at least heard of this equation and are aware of its tremendous impact on the world. However, most people do not know what the equation means. Simply put, this equation represents the correlation of energy into matter: in essence, energy and matter are two forms of the same thing. This simple equation has changed the way we think about energy and has given rise to various technological advances.
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Part 1 of 2: Understanding Equations
Step 1. Define the equation variables
The first step to understanding the equation is knowing the meaning of each of the variables. In this case, E is the energy of a stationary object, m is the mass of the object, and c is the speed of light in a vacuum.
The speed of light (c) is a constant which is equal in each equation and is approximately equal to 3.00x108 meters per second. In the context of Einstein's relativity, c2 functions more as a unit conversion factor than a constant. Therefore, c is squared as a result of the dimensional analysis (energy is measured in joules, or kg m2 s-2) so that the addition of c2 to ensure that the relationship between energy and mass is dimensionally consistent.
Step 2. Understand what energy is
There are many forms of energy, including heat, electricity, chemicals, nuclear, and others. Energy is transferred between various systems (providing power to one system while drawing energy from another).
Energy cannot be created or destroyed, only transformed into different forms. For example, coal has a lot of potential energy that turns into heat energy when burned
Step 3. Define the notion of mass
Mass is generally defined as the amount of matter in an object.
- There is also another definition of mass. There are terms "rest energy" and "relativistic mass". Rest energy is mass that is constant and does not change, no matter what frame of reference you use. On the other hand. relativistic mass depends on the velocity of the object. In the equation E = mc2, m refers to the rest energy. This is very important, because it means your mass no increases even if you pick up speed, contrary to popular belief.
- It should be understood that mass and weight are two different things. Weight is the gravitational force felt by an object, while mass is the amount of matter in the object. Mass only changes if the object is physically altered, while weight changes depending on the gravity of the object's surroundings. Mass is measured in kilograms (kg) while weight is measured in Newtons (N).
- Like energy, mass cannot be created or destroyed, but it can change form. For example, ice cubes melt into liquid, but still have the same mass in both types of forms.
Step 4. Understand that mass and energy are equivalent
This equation states that mass and energy are equivalent, and tells how much energy is contained in a given amount of mass. Basically, this equation explains that a small mass is actually full of great energy.
Part 2 of 2: Applying Equations in the Real World
Step 1. Understand where the energy used comes from
Most of the energy we consume comes from burning coal and natural gas. The combustion of these substances makes use of valence electrons (unpaired electrons in the outermost shell of atoms) and bonds made with other elements. When heat is added, these bonds are broken and the energy released is used as a power source.
Obtaining energy through this method is very inefficient and damaging to the environment
Step 2. Apply Einstein's equations to make the energy conversion more efficient
E = mc2tells us that there is more energy stored in the nucleus of an atom than in the valence electrons. The energy released from atomic fission is much higher than that of breaking electron bonds.
Nuclear power is based on this principle. Nuclear reactors cause atomic fission and capture large amounts of energy released
Step 3. Discover the technologies created by E = mc2.
E = mc2 has allowed the creation of many new and exciting technologies, among which we have become our primary needs:
- A PET scan uses radioactivity to see what's inside the body.
- This equation allows for the development of telecommunications with satellites and rover.
- Radiocarbon dating uses radioactive decomposition based on this equation to determine the age of ancient objects.
- Nuclear energy provides a cleaner and more efficient energy source for our society.
