Today’s interesting fact has to do with the element carbon.

There are three common isotopes of carbon that are found on earth, carbon-12, carbon-13 and carbon-14. Around 99% is carbon-12, about 1% is carbon-13 and carbon-14 is found in trace amounts.

Carbon-14 is radioactive and decays into nitrogen-14. You might think that this is why carbon-14 is so rare and that it might eventually disappear, but carbon-14 is produced when cosmic rays enter the atmospheres, produce neutrons, through a reaction convert the nitrogen-14 into a carbon-14 atom and a hydrogen atom.

Carbon-14 is constantly replenished, so that in the there is always about the same amount in the atmosphere at any time. Carbon-14 gets picked up by plants and through herbivores enters the animal food chain. Once an animal or plant dies, the ratio of carbon-14 to the other carbon isotopes doesn’t remain constant, as the carbon decays.

Because we know the half life of carbon-14, and the amount of carbon-14 is thought to remain constant (which remains true as long as the amount of cosmic rays remains constant), by determining how much carbon-14 remains in a sample, can determine how old the sample is, which is how radio-carbon dating works.

Today’s interesting fact has to do with atoms, elements and isotopes.

The simplest atom, hydrogen, has one electron and one proton. The proton is in the nucleus with the electron circling around it. But there isn’t just one form of hydrogen, there are three. Deuterium is an isotope of hydrogen that has a neutron in the nucleus with the proton. Tritium has two neutrons with the proton. Hydrogen is also the only element with separate names for the various isotopes. The simplest form, without any neutrons, is also known as protium.