How to Calculate E = MC2

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It may not be obvious, but a blazing campfire relies on the principles contained in Einstein's famous equation, E = mc^2. This equation demonstrates the relationship between mass and energy. These two properties are interchangeable; if a system loses mass it must gain energy, and vice-versa. In the campfire example, the flames consume some of the mass of the wood, resulting in energy in the form of heat. Calculating E = mc^2 for any object tells you how much energy would result if the entire object disappeared.

    Weigh the object you will perform the calculation for with a mass balance scale. Record its mass.

    Convert the mass to kg, if necessary. To convert from g to kg, for example, divide by 1,000.

    Square the speed of light. The speed of light is approximately, 300,000,000 m per second; (300,000,000 m/s)^2 equals 90,000,000,000,000,000 meters squared per second squared, or 9 x 10^16 m^2/s^2.

    Multiply the result by the mass of the object in kilograms. If the mass is 0.1 kg, for example, (0.1 kg)​(9 x 10^16 m^2/s^2) = 9 x 10^15 kg​m^2/s^2.

    Record the result in Joules, the standard metric unit for energy. One Joule equals 1 kg​m^2/s^2, so 9 x 10^15 kg​m^2/s^2 equals 9 x 10^15 J.

    Things You'll Need

    • Mass balance scale
    • Calculator


    • Convert the result to kilojoules -- abbreviated as kJ -- by dividing by 1,000. The accurate speed of light is 299.792.458 m per second.


About the Author

Petra Wakefield is a writing professional whose work appears on various websites, focusing primarily on topics about science, fitness and outdoor activities. She holds a Master of Science in agricultural engineering from Texas A&M University.