Part 2 of 5 Fission reactions release energy, but where does this energy come from? What form does it take? To understand how energy works in nuclear reactions, we first need to introduce an important concept from the theory of special relativity. This theory, developed by Albert Einstein, predicts that mass and energy are equivalent. That is, the mass of a system is effectively a measurement of the total amount of energy within the system. This is expressed through the famous equation E = mc². where E is the energy of the system, m is the mass of the system, and c is the speed of light in vacuum, which has a constant value of 3.00 x 108 m/s. The factor of c² is therefore a scale factor which relates units of mass to units of energy. When the units of mass are kilograms and the speed of light is in meters per second, the equation gives an energy in joules. Let's try a simple example. A small paper clip has a mass of 5 grams, or 0.005 kg. How much total energy is contained within the paper clip? Express the