Glossary Starting with the letter: N


An electrically neutral atomic particle that is stable when bound in an atomic nucleus. Neutrons are present in all known nuclei except the lightest isotope of hydrogen.

Nitrous Oxide

A colorless gas or liquid (N2O), soluble in water or alcohol. It is a product of the combustion of fossil fuel.

Northern Hemisphere

The half of the planet north of the equator.

Nuclear Fusion

A nuclear reaction in which two light nuclei combine, at extremely high temperatures, to form a heavier nuclei and simultaneously release a vast amount of energy.