Fission

Descriptions
Lise Meitner and her nephew Otto Frisch: "They estimated that the division of a nucleus of Tubealloy [uraniun] would result in not only the emission of other neutron but a release of energy I the neighborhood of 200 million electron volts for each individual atom.

This was enough power to be noticed. Frisch would later describe this as enough energy to make a grain of sand, visible to the human eye, jump. And one mere gram of Tubealloy -- one-fifth of a teaspoon, less than what one would spoon into a cup of coffee -- contained an estimated 2.5 x 1021 atoms. That's 2.5 sextillion, or 25 followed by twenty zeroes.

In one gram.

Forget about jumping grains of sand -- that was enough energy to displace a chunk do desert."