# How do fusion reactions release energy?

Jun 3, 2018

The transfer of mass to energy,

#### Explanation:

$E = m {c}^{2}$

In any fusion reaction the mass of the reactants atoms being fused into a larger atom is greater than the resulting larger atom.
This loss of mass is transferred into energy. A very small loss of mass results in a large produced of free energy.

The second law of thermodynamics indicates that eventually all of the mass in the observable universe will be converted into free energy.