A spark gap consists of two electrodes that are separated—usually by air—to allow a spark to form between them. Small spark gaps are used to ignite combustion in engines, and huge spark gaps are used in high-voltage switches at electrical substations. Spark gaps can also be used in novelty devices such as the "Jacob's ladder," in which electric arcs continuously stream upward between two wires. How are such toys dangerous to houseplants?
L. Frank Baum
Back in the day
At the time he was shot on the grounds of Kentucky's state capitol, William Goebel was not a well-liked man—nor had he technically won the heavily contested 1899 Kentucky gubernatorial election. However, he lived just long enough to be declared governor and sworn into office, making him the only state governor in US history to have been assassinated. The identity of his assassin remains a mystery. Several years before his murder, Goebel shot a political foe in the head. What prompted their duel?
Born on a day like today
One of the most respected leaders of the Latin American wars for independence, Sucre was a close friend and chief lieutenant of Simón Bolívar. He was an able military leader, yet he was known for his kindness to those he defeated. Against his will, he became president of the newly created state of Bolivia and soon resigned. He later returned to service to help repel a Peruvian invasion. At the age of 35, he was waylaid in a mountainous region and killed. He was buried not in Bolivia, but where?