Free radicals can damage the molecular machinery of biological systems, leading to cross-linking and mutation. A quantum-mechanical principle with the consequence that the position and momentum of an object cannot be precisely determined. The Heisenberg principle helps determine the size of electron clouds, and hence the size of atoms. Rules of thumb used to guide one in the direction of probable solutions to a problem. An electronic circuit consisting of many interconnected devices on one piece of semiconductor, typically into 10 millimeters on a side.
ICs are the major building blocks of today's computers.
An atom with more or fewer electrons than those needed to cancel the electronic charge of the nucleus. An ion is an atom with a net electric charge. A spacecraft propulsion system that gains thrust from the pressure of light striking a thin metal film. An idea that, like a gene, can replicate and evolve. See Nanotechnology .