In 1960, astronomers discovered some mysterious space objects and called them quasars because they were discovered to be a strong source of radio waves. In fact, the term “quasar” comes from the words “quasi-stellar radio source.” Quasars are sources of light or radio waves, just like galaxies, that emit enormous amounts of energy.
They are the most distant objects scientists have discovered. They are very bright (as bright as hundreds of galaxies, burning with the energy of 1 trillion Suns) and much smaller than most galaxies. Today, many astronomers refer to these objects as quasi-stellar objects, or QSOs.
The suggestion that storks delivered babies came from Scandinavia and was promoted by the writings of Hans Christian Andersen. Storks had a habit of nesting on warm chimneys and would often lift articles from clotheslines then stuff them into these nests, which to children looked like they were stuffing babies down the flue. The stork is also very nurturing and protective of its young, which helped it become symbolic of good parenthood.
When a hot liquid is poured into a tumbler, the inner layer of the tumbler gets heated, it expands before the outer layer and an unequal expansion of both layers causes the tumbler to crack.
For about six hundred years, from 1250 to 1850, most parts of the world experienced colder and harsher climates than usual. The cooler temperatures were caused by a combination of less solar activity and large volcanic eruptions. Northern Europe’s Little Ice Age took place between 1430 and 1850. When the climate became colder, crops died, and there was widespread famine and disease.
Although it was not a true ice age because it did not get cold enough for long enough to cause ice sheets to grow larger, England experienced some of the coldest winters in its history during the 1820s. Its longest river, the River Thames, froze over regularly and townspeople held Frost Fairs, during which they played games and danced on its icy surface.
Scientists estimate that Earth—born out of a swirling cloud of gas and dust—is about 4.6 billion years old. They have reached this conclusion by studying Moon rocks and meteorites (rocks that have fallen from space to Earth) that they believe were formed at the same time as our planet.
No. Although most of the world’s plants are flowering plants called angiosperms (from the Greek words for “vessel” and “seed”), there are hundreds of plants that do not make flowers. Seed plants that do not have flowers—such as cycads, ginkgo, and conifers—are called gymnosperms. Conifers, for example, are common gymnosperms; instead of flowers, conifers have cones that produce pollen or eggs. Well-known examples are cedars, cypresses, Douglas firs, junipers, pines, redwoods, and spruces.
Male cones are small and soft, and female cones are large and hard. Wind carries pollen from the male cone to the female cone. As the eggs are pollinated and seeds develop, the scales of the cone open up to release the seeds. Once the seeds take root, a new plant grows. Other plants that do not have flowers are mosses; although they sometimes look like they are blooming, the flower-like part is a little capsule full of spores at the end of a small stem.
Pen pals (also called pen friends) are people who regularly write to each other, particularly via postal mail. They are often located in faraway places, such as other states and countries. A pen pal relationship is often used to practice reading and writing in a foreign language, to improve literacy, to learn more about other countries and lifestyles, and to feel connected to people in other parts of the world which helps the world feel like a much smaller place! Pen pals come in all ages, nationalities, and cultures. Pals may seek new pals based on their own age group or a shared common interest, such as a specific sport or hobby, or they may select someone totally different to gain knowledge about a foreign culture (such as the Far East, Europe, or South America). With the advent of the Internet, a modern version on the traditional pen pal arrangement has developed, and many pen pals also exchange e-mail addresses as well as, or instead of, paper letters. In order to connect with a pen pal, get your mom or dad’s permission first. Often, online sites dedicated to pen pal communication can help you connect with a student your own age.
Early in baseball history, a man named Henry Chadwick designed the system we still use for keeping score. Because his system already had an overabundance of Ss scattered throughout his scoresheet — safe, slide, shortstop, sacrifice, second base, etc. — he decided to use the last letter of struck, as in, “he struck out,” rather than the first. And that’s why K signifies a strikeout in baseball.
Motion sickness happens when your body is feeling the sensation of movement. This can happen when you are riding in a school bus, sailing on a boat, or riding in the backseat of a car. When you are reading a book, your eyes do not see the movement, which confuses your brain and causes some people to feel sick. If you get car sick, the solution is to look out the window, not down at your book, so your brain and body will be in sync.
The word curfew comes from the French couvre-feu, which means “cover-fire” and was brought to England by William the Conqueror. The original Curfew Law minimized the tremendous risk of fire by ordaining that a bell be rung at eight o’clock each evening, signalling everyone to either extinguish or cover their home fires. During political unrest, the same curfew bell signalled the public to clear the streets and stay in their homes for the night.