How to Understand E=mc2: 7 Steps (with Pictures) - wikiHow (2024)

  • Categories
  • Education and Communications
  • Studying
  • Science
  • Physics

Download Article

Explore this Article

parts

1Understanding the Equation

2Applying the Equation in the Real World

Other Sections

Video

Related Articles

References

Article Summary

Reviewed byGrace Imson, MA

Last Updated: May 7, 2024Fact Checked

Download Article

In one of Albert Einstein’s revolutionary scientific papers published in 1905, E=mc2 was introduced; where E is energy, m is mass, and c is the speed of light in a vacuum.[1] Since then, E=mc2 has become one of the most famous equations in the world. Even people with no background in physics have at least heard of the equation and are aware of its prodigious influence on the world we live in. However, most people do not exactly know what the equation means. In simple terms, the equation represents the correlation of energy to matter: essentially, energy and matter are but two different forms of the same thing.[2] This relatively simple equation has altered the way we think about energy and provided us with numerous technological advances.

Part 1

Part 1 of 2:

Understanding the Equation

Download Article

  1. 1

    Define the variables of the equation. The first step to understanding any equation is to know what each variable stands for. In this case, E is the energy of an object at rest, m is the object's mass, and c is the speed of light in vacuum.[3]

    • The speed of light, c is constant in all reference frames and is roughly equal to 3.00x108 meters per second. In the context of Einstein's relativity, the c2 functions more as a unit conversion factor than a constant. As such, it is squared as a result of dimensional analysis - energy is measured in joules, or kg m2 s-2, so adding the c2 ensures that the relationship between energy and mass is dimensionally consistent.
  2. 2

    Understand what is meant by energy. There are many forms of energy including thermal, electrical, chemical, nuclear and more.[4] Energy is transferred between systems giving power to one system while taking it away from another.

    • Energy can be neither created nor destroyed, it can only take a different form. For example, coal has a lot of potential energy that turns into thermal energy when it is burned.

    Advertisem*nt

  3. 3

    Define what mass means. Mass is generally defined as the amount of matter in an object.[5]

    • There are also a few other definitions of mass. There exists "invariant mass," and "relativistic mass." Invariant mass is mass that remains unchanged no matter what frame of reference you are in. Relativistic mass, on the other hand, depends on the object's velocity. In the equation E = mc2, m refers to the invariant mass. This is very important, because this means that your mass does not grow as you go faster, contrary to popular belief.
    • It’s important to understand that mass and weight are different. Weight is the gravitational force felt by an object, while mass is the amount of matter in that object. Mass can only change if the object is physically altered, while weight changes depending on the gravity of the environment the object is in. Mass is measured in kilograms (kg) while weight is measured in newtons (N).
    • Like energy, mass can neither be created nor destroyed, but it can also change form. For example, an ice cube can melt into a liquid, but it still has the same mass in both states.
  4. 4

    Realize that mass and energy are equivalent.[6] The equation states that mass and energy are the same thing and tells you how much energy is contained inside a certain amount of mass. Essentially, the equation explains that a small amount of mass is full of a large amount of energy.

  5. Advertisem*nt

Part 2

Part 2 of 2:

Applying the Equation in the Real World

Download Article

  1. 1

    Understand where usable energy comes from. Most of our consumable energy comes from the burning of coal and natural gas. Burning these substances takes advantage of their valence electrons (unpaired electrons in the outermost shell of an atom) and the bonds they make with other elements. When heat is added, these bonds break and the energy released is used to power our communities.

    • Obtaining energy this way is not very efficient and is costly to the environment.
  2. 2

    Apply Einstein’s equation to make energy conversion more efficient. E=mc2 tells us that there is much more energy stored inside the nucleus of an atom than in its valence electrons. The energy released from splitting an atom is much higher than that of breaking electron bonds.

    • Nuclear power is based on this principle. Nuclear reactors cause fission (the splitting of atoms) to occur and capture the massive amount of energy released.
  3. 3

    Discover the technologies made possible by E=mc2. E=mc2 has enabled the creation of many new and exciting technologies, some of which, we can’t imagine living without:[7]

    • PET scans use radioactivity to see inside the body.
    • The equation allowed for the development of telecommunications with satellites and rovers.
    • Radiocarbon dating uses radioactive decay based on the equation to determine the age of ancient objects.
    • Nuclear energy provides cleaner and more efficient energy sources to our society.
  4. Advertisem*nt

Community Q&A

Search

Add New Question

  • Question

    If mass can neither be created nor destroyed as stated in your article, can mass change into energy and vise versa?

    How to Understand E=mc2: 7 Steps (with Pictures) - wikiHow (12)

    Community Answer

    Einstein is basically saying that mass and energy are different forms or descriptions of the same thing. By converting mass to energy, you are still conserving the mass through the form of energy.

    Thanks! We're glad this was helpful.
    Thank you for your feedback.
    If wikiHow has helped you, please consider a small contribution to support us in helping more readers like you. We’re committed to providing the world with free how-to resources, and even $1 helps us in our mission.Support wikiHow

    YesNo

    Not Helpful 30Helpful 123

  • Question

    You use a melting ice cube as an example of an object changing forms without losing mass. But surely the melted water will occupy less volume than the ice cube?

    How to Understand E=mc2: 7 Steps (with Pictures) - wikiHow (13)

    Community Answer

    Mass and volume are not the same. You can stretch or compact an object to change its volume, but the amount of matter inside it will stay the same. In the ice cube example, the molecules in liquid water are closer together, but they're still the same molecules that were in the ice.

    Thanks! We're glad this was helpful.
    Thank you for your feedback.
    If wikiHow has helped you, please consider a small contribution to support us in helping more readers like you. We’re committed to providing the world with free how-to resources, and even $1 helps us in our mission.Support wikiHow

    YesNo

    Not Helpful 55Helpful 313

  • Question

    Can humans travel 1% the speed of light yet?

    How to Understand E=mc2: 7 Steps (with Pictures) - wikiHow (14)

    Community Answer

    No, not even close. Keep in mind that the speed of light is 3.00×10^8 meters/second. For us to even go a fraction of that speed, 1% for example, we would have to go 3.0×10^6 meters/second which is approximately 1,864.1 miles/second or 6,710,808.88 miles/hour. We are not even close to that speed yet technologically.

    Thanks! We're glad this was helpful.
    Thank you for your feedback.
    If wikiHow has helped you, please consider a small contribution to support us in helping more readers like you. We’re committed to providing the world with free how-to resources, and even $1 helps us in our mission.Support wikiHow

    YesNo

    Not Helpful 49Helpful 218

See more answers

Ask a Question

200 characters left

Include your email address to get a message when this question is answered.

Submit

      Advertisem*nt

      Video

      Submit a Tip

      All tip submissions are carefully reviewed before being published

      Submit

      Thanks for submitting a tip for review!

      You Might Also Like

      How toLearn PhysicsHow toMemorize Math and Physics Formulas
      How toGet a Ph.D. in PhysicsHow toBecome a Theoretical PhysicistHow toUnderstand Quantum PhysicsHow toCalculate Tension in PhysicsHow toSolve Any Physics ProblemHow toMake a Faraday CageHow toCalculate ImpedanceHow toCalculate WavelengthHow toCalculate Wind LoadHow toCalculate Center of GravityHow toCalculate Force of Gravity

      Advertisem*nt

      About This Article

      How to Understand E=mc2: 7 Steps (with Pictures) - wikiHow (29)

      Reviewed by:

      Grace Imson, MA

      Math Teacher

      This article was reviewed by Grace Imson, MA. Grace Imson is a math teacher with over 40 years of teaching experience. Grace is currently a math instructor at the City College of San Francisco and was previously in the Math Department at Saint Louis University. She has taught math at the elementary, middle, high school, and college levels. She has an MA in Education, specializing in Administration and Supervision from Saint Louis University. This article has been viewed 1,248,995 times.

      283 votes - 83%

      Co-authors: 57

      Updated: May 7, 2024

      Views:1,248,995

      Categories: Featured Articles | Physics

      Article SummaryX

      To understand E=mc², you have to define each of the variables. E is the energy of an object at rest, m is that object’s mass, and c is the speed of light in a vacuum. Neither the energy nor the mass of an object can change, although the mass can change forms, such as when an ice cube melts. The purpose of the equation is to tell you how much energy is contained in a certain amount of mass. To learn how to apply the equation to the real world, read on!

      Did this summary help you?

      In other languages

      Spanish

      Russian

      Portuguese

      French

      Indonesian

      Dutch

      Thai

      Chinese

      Arabic

      • Print
      • Send fan mail to authors

      Thanks to all authors for creating a page that has been read 1,248,995 times.

      Reader Success Stories

      • How to Understand E=mc2: 7 Steps (with Pictures) - wikiHow (30)

        Peggy McCants

        Jul 4, 2017

        "I never took physics in high school or college, but every day I realize that so much of the world has to do with..." more

      More reader storiesHide reader stories

      Did this article help you?

      Advertisem*nt

      How to Understand E=mc2: 7 Steps (with Pictures) - wikiHow (2024)

      References

      Top Articles
      Latest Posts
      Article information

      Author: Dean Jakubowski Ret

      Last Updated:

      Views: 5739

      Rating: 5 / 5 (50 voted)

      Reviews: 81% of readers found this page helpful

      Author information

      Name: Dean Jakubowski Ret

      Birthday: 1996-05-10

      Address: Apt. 425 4346 Santiago Islands, Shariside, AK 38830-1874

      Phone: +96313309894162

      Job: Legacy Sales Designer

      Hobby: Baseball, Wood carving, Candle making, Jigsaw puzzles, Lacemaking, Parkour, Drawing

      Introduction: My name is Dean Jakubowski Ret, I am a enthusiastic, friendly, homely, handsome, zealous, brainy, elegant person who loves writing and wants to share my knowledge and understanding with you.