How big is the moon?
The moon’s diameter is 2,160 miles.
The earth’s diameter at the equator is 7,926.68 miles.
Plastics are only one kind of polymer, a substance composed of very large chain-like molecules that consist of smaller, repeating chemical units. Natural polymers include proteins, cellulose, diamonds, and quartz. Besides plastics, man-made ones include concrete, glass, and paper.
Brass is an alloy of copper and zinc. Bronze is a more durable mixture of copper and tin.
Contrary to dormitory fears, it does not inhibit sexual desire. Instead, saltpeter, or potassium nitrate (KNO3), is a diuretic. Another form of saltpeter is Chile saltpeter, or impure sodium nitrate (NaNO3). Lime, or Norwegian saltpeter, is calcium nitrate. It is used to make explosives.
Man evolved in the Pleistocene epoch, which began about 2.5 million years ago and ended about 10,000 years ago. We now live in the Recent (or Holocene) epoch, beginning about 10,000 years ago.
Most of the world’s non-Muslim countries use the Gregorian calendar, introduced by Pope Gregory XIII in 1582 as a reform of the Julian calendar. The latter, instituted by Julius Caesar, had been in use since 46 B.C. Americans have used the Gregorian calendar since 1752. What’s the difference between the the Julian or the Gregorian…
The first to approximate the speed of light roughly was French physicist Armand Fizeau (1819-1896). In 1849 Fizeau obtained a value for the speed of light that was about 5 percent too high. Fizeau’s contemporary Jean Foucault (1819-1868) obtained the first accurate measurement (within 1 percent of the correct speed) in 1862.