Created by Todd Eide

Physics 212


" The discovery of nuclear chain reactions need not bring about the destruction of mankind any more than did the discovery of matches. We only must do everything in our power to safeguard against its abuse."

Albert Einstein

If we fight a war and win it with H-bombs, what history will remember is not
the ideals we were fighting for but the methods we used to accomplish them.
These methods will be compared to the warfare of Genghis Khan who ruthlessly
killed every last inhabitant of Persia.

Hans A. Bethe

And these atomic bombs which science burst upon the world that night were strange even to the men who used them.

H. G. Wells, The World Set Free, 1914

In a nuclear reaction, however, the energy released is often about a million times greater than in a chemical reaction, and the change in mass can easily be measured.
Mass and energy are related by what is certainly the best-known equation in physics:


E is the energy equivalent (called mass energy) of mass m, and c is the speed of light.

A very small amount of matter is equivalent to a vast amount of energy.
For example, 1 kg (2.2 lb) of matter converted completely into energy would be equivalent to the energy released by exploding 22 megatons of TNT.