"Democracy's real test lies in its respect for minority opinions." - Ellery Sedgwick

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 Congress repealed the 55 mph national limit in 1995.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.

A perennial stream or perennial river is a stream or river (channel) that has continuous flow in parts of its stream bed all year round during years of normal rainfall. "Perennial" streams are contrasted with "intermittent" streams which normally cease flowing for weeks or months each year, and with "ephemeral" channels that flow only for hours or days following rainfall.

The Peace Corps is a volunteer program run by the United States government. The stated mission of the Peace Corps includes three goals: providing technical assistance; helping people outside the United States to understand American culture; and helping Americans to understand the cultures of other countries.