Video: The Sensory System: Definition, Parts & Functions. This lesson will examine how the sensory systems are integrated and how they function as a whole. Instead of telling you ears hear and eyes see, we will examine how these systems are actually very similar in terms of reception, signals, and translations.
Mercury is a silvery-white metal element that is liquid at ordinary room temperature; it has no taste or smell. It occurs as metallic mercury (Hg), as cinnabar (HgS) and in perhaps 25 other in organic mineral compounds. The elemental form (Hg) vaporizes at any temperature down to almost 40Â° below zero. The vapor also has no taste or smell. The specific gravity of mercury is 13.546; therefore, it is heavier than lead and, like lead and other heavy metals, it is a potent poison. Exposure to metallic mercury or mercury compounds, even in small quantities over a period of time, can cause severe poisoning.
Mercury is a naturally-occurring chemical element found in rock in the earth's crust, including in deposits of coal. On the periodic table, it has the symbol Hg and its atomic number is 80. It exists in several forms: methylmercury and other organic compounds, elemental (metallic) mercury, and; inorganic mercury compounds. Methylmercury and other organic mercury compounds are formed when mercury combines with carbon. Microscopic organisms convert mercury into methylmercury, which is the most common organic mercury compound found in the environment. Elemental or metallic mercury is a shiny, silver-white metal and is liquid at room temperature. It is used in older thermometers, fluorescent light bulbs and some electrical switches.