Matter & Energy


Matter is composed of atoms or groups of atoms called molecules. The arrangement of particles in a material depends on the physical state of the substance. In a solid, particles form a compact structure that resists flow. Particles in a liquid have more energy than those in a solid. They can flow past one another, but they remain close. Particles in a gas have the most energy. They move rapidly and are separated from one another by relatively large distances.

Cocaine

Cocaine is an alkaloid obtained from leaves of the coca plant and used medically as a local anesthetic (see Anesthesia). It is also widely abused as a drug. Native Americans of the Inca Empire chewed coca leaves to obtain mild euphoria, stimulation, and alertness.

Cocaine hydrochloride, a water-soluble salt, is a dry white powder (known on the street as “snow”) that is usually inhaled through a thin tube inserted into the nostril. More rarely, cocaine is injected into a vein. The drug may also be smoked in a purified form through a water pipe (“freebasing”) or in a concentrated form (“crack”) shaped into pellets and placed in special smoking gear. Users experience euphoria, exhilaration, and a decreased appetite. The drug also increases heart rate, elevates blood pressure, and dilates the pupils. Chronic use can lead to skin abscesses, perforation of the septum of the nose, weight loss, and damage to the nervous system. Negative mental effects include extreme restlessness, anxiety, irritability, and, occasionally, paranoid psychosis. Death from even a small dose can occur, and is usually caused by seizures or heart attacks.