America’s founders did debate a bit as to whether or not to force children to attend schools, and they decided to leave such decisions to individual families and local and state governments. The words “education” and “school” do not appear in any of our founding documents, such as the Declaration of Independence, the Constitution, or the Bill of Rights.
Some of our most famous inventors, writers, and politicians were self-taught, learning through mentoring or apprenticeships, conversation, and reading. In 1850, Massachusetts became the first state to institute a compulsory schooling law.
Earth is more active, in terms of both geology and weather, which makes it hard for craters to remain. Even those craters scientists can see on the surface—which may be millions of years old—have been overgrown by vegetation, weathered by wind and rain, and changed by earthquakes and landslides. The Moon, meanwhile, is geologically quiet and has almost no weather, so its hundreds of thousands of craters are easy to see.
The craters are the result of both meteorites and volcanic activity. Interestingly, some of the oldest Earth rocks might be awaiting discovery on the Moon, having been blasted there billions of years ago by asteroid impacts that shook both worlds.
The first primitive plants appeared on land about 470 million years ago. But these plants did not look like the lush greenery we see in the world today. Rather, they were rootless patches of thin, leaflike plants called liverwarts, so named because some species look like green livers. Liverwarts used a specialized filament (called a rhizoid) to absorb water and stick to rocks.
Fossils reveal that the first true plants to colonize land appeared about 420 million years ago. These plants included flowerless mosses, horsetails, and ferns. They reproduced by throwing out spores, or minute organisms that carried the genetic blueprint for the plant. The ferns eventually bore seeds, but not until about 345 million years ago. Plants with roots, stems, and leaves (called vascular plants) evolved about 408 million years ago.
The Nobel Prize is the most famous international science award. Three science prizes, for chemistry, physics, and physiology or medicine, are awarded every year to people who have made significant contributions to these fields. The prize was created by the Swedish chemist and industrialist Alfred Nobel, who made a fortune from his invention of dynamite and left much of his money to fund the prize. Since 1901, the Nobel Prize has been honoring men and women from all parts of the world for their discoveries and inventions in these areas, as well as in the fields of literature and peace.
Some famous scientists and inventors who have been awarded the prize include Ivan Pavlov (in 1904), Albert Einstein (1921), and Linus Pauling (1954). Eleven women, from a total of 500 scientists, have been awarded a Nobel Prize in the sciences from 1901 to 2008. Among them, Marie Curie is the only person ever to have twice received a Nobel Prize in the sciences, each time in a different field of specialization: in Physics, in 1903, and in Chemistry, in 1911.
The Statue of Liberty stands for many of the nation’s most cherished ideals: freedom, equality, and democracy. Perhaps most importantly to the millions of immigrants for whom the statue was one of their first sights of the United States, it stands for the ideal of opportunity—the chance to begin a new life, in a new land. While their lives in the United States were frequently difficult, for millions of immigrants America offered the chance to escape from grinding poverty and abusive governments in other lands. Standing in the midst of New York Harbor, the point of entry into the United States for so many immigrants arriving on ships from other countries, the Statue of Liberty has been a powerful symbol of opportunity for more than 100 years.
A poem called “The New Colossus,” written by Emma Lazarus, was mounted on the statue’s pedestal in the early 1900s. Its famous lines include these words that Lazarus imagined Lady Liberty to be saying: Give me your tired, your poor, Your huddled masses yearning to breathe free, The wretched refuse of your teeming shore; Send these, the homeless, tempest-tost to me, I lift my lamp beside the golden door!
Today, about 3.5 percent of ocean water is salt. When planet Earth was still young, its atmosphere contained a mix of hydrogen chloride, hydrogen bromide, and other gasses from volcanoes. Oceanographers (scientists who study the ocean) believe that some of these gases dissolved in the early ocean, making it salty.
Today, however, most of the salt in the oceans comes from rain. Rain falling on the land dissolves the salts in eroding rocks, and these salts are carried down the rivers and out to sea. The salts accumulate in the ocean as water evaporates to form clouds. The oceans are getting saltier every day, but the rate of increase is so slow that it hard to measure. If the oceans suddenly dried up, there would be enough salt to build a 180-mile- (290-kilometer) tall wall around the equator.
The word “toadstool” dates to the Middle Ages when it was associated with the toad, Which was thought to be poisonous. Toadstools, with their stool-like shape, are really mushrooms that are poisonous or inedible.
For example, the bright red “fly agaric” toadstool’s juice was once used to make a remedy for killing bugs. It is a very poisonous mushroom that still lives today and should be avoided.
Unlike the fragrant blossoms that attract bees, carrion flowers simulate the odor of a rotting animal carcass and attract carrion beetles and different types of flies, including blowflies, flesh flies, and midges. The stapelia flower, which is shaped like a starfish and grows in Africa, has fine hairs around its petals, perhaps to imitate the appearance of a small dead animal. When the bloom opens it gives off a rotting smell, imitating dead animal meat.
The smell attracts flies, which collect pollen before they fly away. Some carrion flowers, such as the European and Brazilian Dutchman’s pipe, lure insects into dark openings that lead to the foul-smelling interior where they become trapped. When the flower “releases” the insect, it is coated with fresh pollen to be taken to a different plant. The lantern stinkhorn, a fungus that releases a feces-like odor, attracts green bottle flies to spread its spores.
Pythagoras was one of the first Greek mathematical thinkers. He is known for proving and teaching the Pythagorean Theorem, which says that in a right triangle, the sum of the squares of the two right-angle sides will always be the same as the square of the hypotenuse (the long side). He lived in the 500s B.C.E., and spent most of his life in the Greek colonies in Sicily and southern Italy. He had a group of followers Who studied with him and taught other people what he had taught them.
The Pythagoreans were known for their pure lives (they did not eat beans, for example, because they believed that beans were not a pure food). They wore their hair long, wore only simple clothing, and went barefoot. Both men and women Pythagoreans were interested in philosophy, but especially in music and mathematics, which they believed were two ways of making order out of chaos. Nichomachus of Gerasa was a Pythagorean of the first and second centuries. His ideas about arithmetic built upon Pythagoras’s ideas of the harmonic sounds of the motions of the planets and the proportional relationships of numbers.
Guglielmo Marconi, of Bologna, Italy, was the first to prove that radio signals could be sent over long distances. Radio is the radiation and detection of signals spread through space as electromagnetic waves to convey information.
It was first called wireless telegraphy because it duplicated the effect of telegraphy without using wires. On December 21, 1901, Marconi successfully sent Morse code signals from Newfoundland to England.