Graphology - the study of handwritings; autograph - written with one's own hand; seismograph - a machine noting strength and duration of earthquakes. marina - a harbor for pleasure boats; maritime - relating to the sea; submarine - an undersea boat; aquamarine - color of sea water.
Chemicals are classified into various hazard classifications in accordance with their physiochemical properties and health hazards. Each class of chemical has a pictorial symbol called a danger symbol.
--used in determining ages of rocks, killing bacteria in food, treatment of cancer, and can follow the movement of substances in organisms. compounds (chemical) -a substance formed by the chemical combination of two or more elements in definite proportions (comparative relation) -compounds are special. --the physical and chemical properties of a compound are usually very different from those of the elements from which it is formed. --the properties are shown by a chemical formula. ----ex.) Water is H2O, table salt is NaCl, etc.