What causes the most household accidents?
The Consumer Product Safety Commission reports that the five most dangerous sources are:
stairs, glass doors, cutlery, glass bottles and jars, and home power tools.
Chinese astronomers made the first recorded observation of Halley’s comet in 240 B.C. In 1705, English astronomer Edmund Halley was the first to theorize that comets travel in regular orbits around the sun. Proposing that “the great comet” observed in 1682 made periodic visits about every 76 years, he predicted that it would return in…
Bird guano is the accumulated excrement and remains of birds such as cormorants, pelicans, and gannets. Guano is 11 to 16 percent nitrogen, 8 to 12 percent phosphoric acid, and 2 to 3 percent potash. The excellent fertilizer is harvested from islands off Peru, Baja California, and Africa. Bat and seal guano is also highly…
Charles Darwin did not come up with the phrase survival of the fittest. The British philosopher and scientist Herbert Spencer introduced the phrase in Principles of Biology (1864-1867) as a way of describing Darwin’s theory of natural selection.
The first leap year was 46 B.C. It was then that the Julian calendar of 365.25 days was adopted. The calendar required that an extra day be added every fourth year.
The earliest era of geologic time is the Precambrian age. It began when the earth’s crust formed, 4.6 billion years ago, and ended with the dawn of the Cambrian period, 570 million years ago. About seven-eighths of earth’s history since the formation of the crust took place during the Precambrian age.
As of 1990, 53 percent of Americans drink fluoridated water. Of these, 121 million drink artificially fluoridated water; 9 million drink water from naturally fluoridated sources.