Category: atom

Structure of the radium atom. Drawing by Niels Bohr, 1922.

A note on Nuclear Fission

When
an atom fissions, it releases a teeny tiny amount of energy ( The decay of one atom of uranium-235 releases about 200MeV or about 3*10-11J.). But atoms
are quite small. An atom does not make a big explosion when
it splits.

To get a big explosion, you need to split lots and lots and
lots and lots and lots and lots and lots and lots and lots of them—many,
many trillions of them.

Each one releases only a teeny amount of
energy, but when you add up the teeny amount of energy from trillions
and trillions and trillions of atoms, then you get a big explosion. (The explosion of 1kg of TNT releases 4MJ).

New Podcast! The quantum rule that makes existence possible

At a fundamental level, everything we know of in this Universe is made of the same few fundamental particles: quarks, gluons, electrons and photons, which combine to give us atoms, which in turn make up all the molecules, cells, organs and living creatures inhabiting our world today. But how do we go from these tiny scales where everything looks so similar to the huge diversity of what exists at a larger, more macroscopic scale?

The secret is encoded in a single quantum rule that governs how it all works: the Pauli exclusion principle. Come get the scoop here on the latest Starts With A Bang podcast!