The Cause of Radioactivity

Radioactivity is caused by emission of high energy radiation from unstable atomic nuclei. An atomic nucleus will be unstable if it has an excess of energy caused by an excess of either neutrons or protons. The nucleus will decay into a more stable atom (usually a different element) from the parent atom. ©Wikipedia An atom …

Chemical Composition Of Meteorites

Meteorites are the remains of space rocks that have fallen to Earths surface (a space rock still in space is termed a meteoroid , and when it is plunging through Earths atmosphere it is termed a meteor) . The small number of meteorites that survive vaporization in the atmosphere relatively intact give a picture of …

Collision theory

Collision theory states that when suitable particles of the reactant hit each other with correct orientation, only a certain amount of collisions result in a perceptible or notable change; these successful changes are called successful collisions. ©Socratic Collision theory was proposed independently by Max Trautz in 1916 and William Lewis in 1918. Consider the bimolecular elementary reaction: A + B → …

Uranium Glass

Uranium glass is glass which has had uranium, usually in oxide diuranate form, added to a glass mix before melting for colouration. The proportion usually varies from trace levels to about 2% percent uranium by weight, although some 20th-century pieces were made with up to 25% uranium. Having been first identified in 1789 by a …

Fullerene

Fullerene is an allotrope of carbon whose molecule consists of carbon atoms connected by single and double bonds so as to form a closed or partially closed mesh, with fused rings of five to seven atoms. The molecule may be a hollow sphere, ellipsoid, tube, or many other shapes and sizes. Since each carbon atom …

Polymer

Polymer  is a substance or material consisting of very large molecules, or macromolecules, composed of many repeating subunits. Due to their broad spectrum of properties, both synthetic and natural polymers play essential and ubiquitous roles in everyday life. Polymers range from familiar synthetic plastics such as polystyrene to natural biopolymers such as DNA and proteins …

Nuclear chain reaction

Nuclear chain reaction occurs when one single nuclear reaction causes an average of one or more subsequent nuclear reactions, thus leading to the possibility of a self-propagating series of these reactions. The specific nuclear reaction may be the fission of heavy isotopes (e.g., uranium-235, 235U). The chain reaction requires both the release of neutrons from fissile isotopes undergoing nuclear fission …

Superheating

Superheating is the phenomenon in which a liquid is heated to a temperature higher than its boiling point, without boiling. This is a so-called metastable state or metastate, where boiling might occur at any time, induced by external or internal effects. Superheating is achieved by heating a homogeneous substance in a clean container, free of …

Crystal

Crystal is a solid material whose constituents (such as atoms, molecules, or ions) are arranged in a highly ordered microscopic structure, forming a crystal lattice that extends in all directions. In addition, macroscopic single crystals are usually identifiable by their geometrical shape, consisting of flat faces with specific, characteristic orientations. Examples of large crystals include …

Intermolecular force

Intermolecular force is the force that mediates interaction between molecules, including the electromagnetic forces of attraction or repulsion which act between atoms and other types of neighboring particles, e.g. atoms or ions. Intermolecular forces are weak relative to intramolecular forces – the forces which hold a molecule together. For example, the covalent bond, involving sharing …