Physics

Polonium Definition Polonium is a radioactive metallic element, occurring naturally in small quantities as a product of radium disintegration and produced synthetically by bombarding bismuth…

Bismuth Definition Bismuth is a brittle, pinkish-white, crystalline metallic element that occurs in nature as a free metal and in various ores. Bismuth is the…

Cadmium Definition Cadmium is a rare, soft, bluish-white metallic element that occurs mainly in zinc, copper, and lead ores. Its atomic number 48; atomic weight…

Atomic Clock Definition Atomic clock is an extremely precise clock whose rate is controlled by a periodic process, such as vibration, or the absorption or…

Caesium Definition Caesium is a soft, ductile, silvery-white element of the alkali group. It is liquid at room temperature and is the most reactive of…

Definition Barium is a soft, silvery-white metallic element of the alkaline-earth group. It occurs only in combination with other elements, especially in barite. It is…

Strontium Definition Strontium is a soft, silvery metallic element of the alkaline-earth group that occurs naturally only as a sulfate or carbonate. It is the…

Rubidium Definition Rubidium is a soft, silvery-white metallic element of the alkali group. It ignites spontaneously in air and reacts violently with water. It is…

About Lithium Definition Lithium is a soft, silvery metallic element of the alkali group that occurs in small amounts in some minerals. It is the…

Aluminium Definition Aluminium is a silvery-white, ductile metallic element, the most abundant in the earth’s crust but found only in combination, chiefly in bauxite. Aluminium…

About Bronze Definition Bronze is a yellow or brown alloy of copper and tin, sometimes with small amounts of other metals such as lead or…

Ceramic Definition Ceramic are any of various hard, brittle, heat- and corrosion-resistant materials made typically of metallic elements combined with oxygen or with carbon, nitrogen,…