Calcium is a chemical element in the periodic table that has the symbol Ca and atomic number 20. Calcium is a soft grey alkaline earth metal that is used as a reducing agent in the extraction of ... > more
Plutonium is a radioactive, metallic, chemical element. It has the symbol Pu and the atomic number 94. It is the element used in most modern nuclear weapons. The most important, albeit not most ... > more
Beryllium is the chemical element in the periodic table that has the symbol Be and atomic number 4. A toxic bivalent element, beryllium is a steel grey, strong, light-weight yet brittle, alkaline ... > more
A calorie is an unit of measurement for energy. The calorie was never a metric or SI unit. In most fields, it has been replaced by the joule, the SI unit of energy.
It remains, however, in common ... > more
Special relativity inter-relates space and time in such a way that the speed of light is constant, and the theory leads to situations where two observers can disagree over time intervals and ... > more
A particle accelerator is a device that uses electric fields to propel electrically charged particles to high speeds and magnetic fields to contain them. An ordinary CRT televison set is a simple ... > more
A hygroscopic substance is one that readily attracts water from its surroundings, through either absorption or adsorption. Examples include honey, glycerin, ethanol, methanol, concentrated sulfuric ... > more