Heavy Metal

Heavy metals

Heavy metals is a controversial and ambiguous term for metallic elements with relatively high densities, atomic weights, or atomic numbers. The criteria used, and whether metalloids are included, vary depending on the author and context, and arguably, the term "heavy metal" should be avoided. A heavy metal may be defined on the basis of density, atomic number, or chemical behaviour. More specific definitions have been published, none of which has been widely accepted. The definitions surveyed in this article encompass up to 96 of the 118 known chemical elements; only mercury, lead, and bismuth meet all of them. Despite this lack of agreement, the term is widely used in science. A density of more than 5 g/cm3 is sometimes quoted as a commonly used criterion and is used in the body of this article.

Metal toxicity

Metal toxicity or metal poisoning is toxicity affecting plants, animals, or humans due to excessive concentration of metals. At low concentrations, metals such as copper, iron, manganese, and zinc are essential nutrients obtained through the diet supporting health, but have toxicity at high exposure concentrations. Other metals having no biological roles in animals, but with potential for toxicity include arsenic, cadmium, lead, mercury, and thallium. Exposure to metals, primarily due to occupational exposure or environmental pollution, can increase metal concentration into hazardous range.

Heavy Metal (film)

Heavy Metal is a 1981 Canadian adult animated science fantasy anthology film directed by Gerald Potterton and produced by Ivan Reitman and Leonard Mogel, who also was the publisher of Heavy Metal magazine, which was the basis for the film. It starred the voices of Rodger Bumpass, Jackie Burroughs, John Candy, Joe Flaherty, Don Francks, Martin Lavut, Marilyn Lightstone, Eugene Levy, Alice Playten, Harold Ramis, Percy Rodriguez, Susan Roman, Richard Romanus, August Schellenberg, John Vernon, and Zal Yanovsky. The screenplay was written by Daniel Goldberg and Len Blum.

Metal

A metal is a material that, when polished or fractured, shows a lustrous appearance, and conducts electricity and heat relatively well. These properties are all associated with having electrons available at the Fermi level, as opposed to nonmetallic materials which do not. Metals are typically ductile and malleable.

heavy metal

Noun

1. Any metal that has a specific gravity greater than about 5, especially one, such as lead, that is poisonous and may be a hazard in the environment. (There are many different definitions of what counts as a heavy metal; see Heavy metals for a discussion.)
2. A genre descended from rock music, characterized by the use of emphatic drumbeats, highly amplified distortion, and overall loudness; often featuring extended instrumental solos and powerful vocals.