Physics Glossary – N


The development and use of devices that have a size of only a few nanometres. Considerable interest has been shown in the production of structures on a molecular level by suitable sequences of chemical reactions or lithographic techniques. It is also possible to manipulate individual atoms on surfaces using a variant of the atomic force microscope to make, for example, high density data storage devices. Also Known As: Nano Machines, micromachines, micro machines. The first mention of this technology was in a talk given by Richard Feynman in 1959.


A lepton with no electric charge. Neutrinos participate only in weak and gravitational interactions and are therefore very difficult to detect. There are three known types of neutrinos, all of which have very little mass.


An uncharged elementary particle found in the nucleus of every atom except hydrogen. A baryon with electric charge zero; it is a fermion with a basic structure of two down quarks and one up quark (held together by gluons). The neutral component of an atomic nucleus is made from neutrons. Different isotopes of the same element are distinguished by having different numbers of neutrons in their nucleus.


The center, usually of the central piece of an atom. The nucleus of an atom is composed of protons and neutrons, which are, in turn, composed of quarks. The nucleus of an atom is about 1000 to 10,000 times smaller than the size of an atom. The size of the atom is defined by the orbit of the electrons.

Newton’s Rings

A curved piece of glass on a flat piece of glass is illuminated from above. A pattern of rings (light and dark) appears in the curved piece of glass. This is a result of interference from reflection.

Neutron Star

Neutron stars are one of the possible ends for a star. They result from massive stars which have mass greater than 4 to 8 times that of our sun. After these stars have finished burning their nuclear fuel, they undergo a supernova explosion. This explosion blows off the outer layers of a star into a beautiful supernova remnant. The central region of the star collapses under gravity. It collapses so much that protons and electrons combine to form neutrons. Hence the name “neutron star”.