Jun 27, 2016

How Hurricanes Form

Tropical cyclones (hurricanes, typhoons) form and grow over warm ocean water, drawing their energy from latent heat. Latent heat is the energy released when water vapor in rising hot, humid air condenses into clouds and rain. As warmed air rises, more air flows into the area where the air is rising, creating wind. The Earth’s rotation causes the wind to follow a curved path over the ocean (the Coriolis effect), which helps give tropical cyclones their circular appearance.

Hurricanes and tropical cyclones form, maintain their strength, and grow only when they are over ocean water that is approximately 27°C (80°F). Such warmth causes large amounts of water to evaporate, making the air very humid. This warm water requirement accounts for the existence of tropical cyclone seasons, which occur generally during a hemisphere’s summer and autumn. Because water is slow to warm up and cool down, oceans do not become warm enough for tropical cyclones to occur in the spring.

Oceans can become warm enough in the summer for hurricanes to develop, and the oceans also retain summer heat through the fall. As a result, the hurricane season in the Atlantic Basin, which comprises the Atlantic Ocean, Caribbean Sea, and the Gulf of Mexico, runs from June 1 through November 30. At least 25 out-of-season storms, however, have occurred from 1887 through 2003, and 9 of these strengthened into hurricanes for at least a few hours.

Jun 15, 2016

Sperm whales exhibit cultural component to their lives

New ways to grab dinner, the trick to using a tool, and learning the local dialect. These are behaviors that animals pick up from each other. Killer whales, chimpanzees, and birds seem to have a cultural component to their lives. Now a new study suggests that sperm whales should be added to that list.

The ocean around the Galápagos Islands hosts thousands of female sperm whales and their calves that have organized into clans with their own dialects. (Mature males congregate in colder waters near the poles.) How these clans form has been something of a mystery until now.

A study published recently in the journal ‘Nature Communications’ suggests that culture—behaviors shared by group members—keeps these sperm whale clans together. Specifically, these deep-diving whales have a distinct series of clicks called codas they use to communicate during social interactions.

Sperm whales with similar behaviors spend time together, and they pick up vocalizations from each other. Scientists call this social learning. Whales that "speak the same language" stick together, giving rise to the clans that researchers have observed for more than 30 years.

Jun 10, 2016

Theodore Roosevelt - 26th President of the United States (1901-1909)

(October 27, 1958 – January 6, 1919)
A writer, naturalist, and soldier. He expanded the powers of the presidency and of the federal government in support of the public interest in conflicts between big business and labour and steered the nation toward an active role in world politics, particularly in Europe and Asia. He won the Nobel Prize for Peace in 1906 for mediating an end to the Russo-Japanese War, and he secured the route and began construction of the Panama Canal (1904–14).

Roosevelt was the second of four children born into a long-established, socially prominent family of Dutch and English ancestry; his mother, Martha Bulloch of Georgia, came from a wealthy, slave-owning plantation family. In frail health as a boy, Roosevelt was educated by private tutors. From boyhood, he displayed intense, wide-ranging intellectual curiosity. He graduated from Harvard College, where he was elected to Phi Beta Kappa, in 1880. He then studied briefly at Columbia Law School but soon turned to writing and politics as a career. In 1880 he married Alice Hathaway Lee, by whom he had one daughter, Alice. After his first wife's death, in 1886 he married Edith Kermit Carow (Edith Roosevelt), with whom he lived for the rest of his life at Sagamore Hill, an estate near Oyster Bay, Long Island, New York. They had five children: Theodore, Jr., Kermit, Ethel, Archibald, and Quentin.

Jun 5, 2016

Clouds

Clouds are condensed form of atmospheric moisture consisting of small water droplets or tiny ice crystals. Clouds are the principal visible phenomena of the atmosphere. They represent a transitory but vital step in the water cycle, which includes evaporation of moisture from the surface of the earth, carrying of this moisture into higher levels of the atmosphere, condensation of water vapor into cloud masses, and final return of water to the surface as precipitation.

The formation of clouds caused by cooling of the air results in the condensation of invisible water vapor that produces visible cloud droplets or ice particles. Cloud particles range in size from about 5 to 75 micrometers (0.0005 to 0.008 cm/0.0002 to 0.003 in). The particles are so small that light, vertical currents easily sustain them in the air. The different cloud formations result partly from the temperature at which condensation takes place. When condensation occurs at temperatures below freezing, clouds are usually composed of ice crystals; those that form in warmer air usually consist of water droplets. Occasionally, however, supercooled clouds contain water droplets at subfreezing temperatures. The air motion associated with cloud development also affects formation. Clouds that develop in calm air tend to appear as sheets or stratified formations; those that form under windy conditions or in air with strong vertical currents have a towering appearance.