Fusion Reactions

Fusion reactions occur when two smaller elements (known as nuclides) collide and fuse into a larger element. The resulting mass of the larger element is minimally smaller than the combined masses of the two fusing elements. This is referred to as the mass defect.

Einstein proposed that energy and mass are related in his equation, E = mc². In this equation energy is equal to the mass multiplied by the speed of light squared. The speed of light is an extremely large number, so even the smallest amount of mass will produce tremendous amounts of energy. The minimal amount of mass that is lost during a fusion reaction is converted to energy as per Einstein’s equation. Due to the amount of energy created, nuclear fusion is used in hydrogen bombs and is also the power source of the sun and surrounding stars.

Examples:

1. The nuclear fusion reaction in a hydrogen bomb.



In this reaction, deuterium ( ) and tritium ( ) are fused into a helium nucleus with the release of a neutron.

2. One of the nuclear fusion reactions that occur in the sun.



In this reaction, two hydrogen atoms are fused into a deuterium atom with the release of a positron ( ).