The Doppler effect (or Doppler shift), named after the Austrian physicist Christian Doppler, who proposed it in 1842 in Prague, is the change in frequency of a wave (or other periodic event) for an observer moving relative to its source. It is commonly heard when a vehicle sounding a siren or horn approaches, passes, and recedes from an observer. The received frequency is higher (compared to the emitted frequency) during the approach, it is identical at the instant of passing by, and it is lower during the recession.

Ohio started the month of July with its pedal to the metal. The Buckeye State became the 34th state to adopt the 70 miles-an-hour speed limit. Drivers can now do up to 70 on more than 570 of Ohio's 1,332 miles of interstate highway. Congress repealed the 55 mph national limit in 1995. Despite predictions of calamity and carnage on the highways, the National Highway Traffic Safety Administration reported in October 1998 that "the traffic death rate dropped to a record low level in 1997". That pattern has continued since then.

Longtime Attorney General Darrell McGraw was a fierce enforcer of state consumer protection laws, winning billions from firms and fly-by-night outfits that committed consumer violations. For West Virginia illness and death caused by cigarettes, McGraw won two lawsuit settlements from 23 tobacco firms for $1.7 billion and $200 million. In 2002, McGraw won $56 million from 15 coal companies that used "independent contractors" to duck state workers' compensation obligations.

Plasma is one of the four fundamental states of matter (the others being solid, liquid, and gas). Heating a gas may ionize its molecules or atoms (reducing or increasing the number of electrons in them), thus turning it into a plasma, which contains charged particles: positive ions and negative electrons or ions.

Pragmatism is a philosophical tradition that began in the United States around 1870. Pragmatism is a rejection of the idea that the function of thought is to describe, represent, or mirror reality. Instead, pragmatists develop their philosophy around the idea that the function of thought is as a instrument or tool for prediction, action, and problem solving. Pragmatists contend that most philosophical topics - such as the nature of knowledge, language, concepts, meaning, belief, and science - are all best viewed in terms of their practical uses and successes rather than in terms of representative accuracy.