This edition: The Behavior Of Atoms: Phases of Matter and the Properties of Gases
By documenting how particles behaved in different states of matter, 19th century scientists gained a deeper understanding of the atom. Avogadro's suggestion that a volume of any gas, under equal temperature and pressure, contains the same number of particles, led to an understanding of the relationship between temperature and pressure and to the Ideal Gas Law. Today, a fourth state of matter, the supercritical fluid, may possibly help mitigate the impact of burning fossil fuels by storing carbon dioxide as a supercritical fluid within the Earth. Researchers are developing methods to pack hydrogen gas into carbon nanostructures for use as fuel in hydrogen-powered vehicles.