A bicycle is a simple device that increases the power that you have in the muscles of your legs, taking you faster and farther than you could ever run. When you push the pedals of your bike around once, the pedal sprocket—the wheel with teeth to which the pedals are attached—goes around once, too. But it pulls a chain along, one that is connected to a much smaller sprocket (with fewer teeth to grip each link of the chain) in the center of your bike’s rear wheel. This smaller sprocket moves around a number of times for each single turn of your pedals, moving your bike wheels a lot faster than you’re moving your feet! Some bicycles have several “speeds,” which means that they have a number of gears (called derailleurs) that vary the rate at which the wheels turn. These extra sprockets are located at the pedals and rear wheel of a bike, where levers move the driving chain sideways, from one to another.
A special spring system keeps the chain tight when it changes from a larger to a smaller sprocket. Although you might think that a rider would always want the wheels of his or her bike to move as fast as possible for each pedal turn, that is not always the case. When going uphill, for instance, a rider can get more force out of a wheel that turns fewer times, making the task easier.
The word fortnight is a unit of time that equals fourteen days. It comes from the Old English word feorwertyne niht, meaning “fourteen nights.” The term is used in Great Britain, where salaries and most social security benefits are paid on a fortnightly basis, but in the United States people use the term “two weeks.”
In many languages, there is no single word for a two-week period and the equivalent of “fourteen days” has to be used. In Spanish, Italian, French, and Portuguese, the terms quince días, quindicina, quinzaine, and quinzena—all meaning “fifteen days”—are used.
Yes. Yet unlike a few centuries ago, gold panning today is primarily a recreational activity. Gold nuggets are found in areas where lode deposits and erosion have occurred—for example, in streams, rivers, ravines, and lake areas. All you need is a gold pan, a shovel, and a lot of patience. Both gold mines and gold prospecting sites exist in national parks from near Montgomery, Alabama to Washington, D.C. In addition, North Carolina, South Carolina, Georgia, Virginia, and Alabama have many gold mines and prospecting sites.
These states were America’s main source of gold for 45 years before the California Gold Rush of 1838, when gold was discovered at Sutter’s Mill in Coloma, California. Its news spread like wildfire, resulting in some 300,000 people coming to California to pan for gold. In California, the five counties of Mariposa, Tuolumne, Calaveras, Amador, and El Dorado—nicknamed the “Mother Lode”—still have gold for discovery. In 1837, the U.S. government established gold coin mints in Georgia and North Carolina to avoid transporting the raw gold to the U.S. Mint in Philadelphia, where coins are made.
Cotton, which comes from flowering Gossypium plants, is a key vegetable fiber used for making clothes, and oil from its seeds can be used in cooking or for making soap. The cotton plant grows in 17 states that make up the U.S. “Cotton Belt”: California, Arizona, New Mexico, Texas, Oklahoma, Arkansas, Missouri, Mississippi, Alabama, Louisiana, Florida, Tennessee, North Carolina, South Carolina, Virginia, Georgia, and Kansas. In the United States, where cotton is no longer picked by hand, machines called pickers or strippers harvest the crops.
Cotton-picking machines have spindles that pick (twist) the seed cotton from the burrs that are attached to plants’ stems. Doffers— a series of circular rubber pads—then remove the seed cotton from the spindles and knock the seed cotton into a conveying system. Conventional cotton stripping machines use rollers equipped with alternating bats and brushes to knock the fluffy white bolls, which contain seeds and hairs, from the plants into a conveyor. After harvest, most of the cotton is pressed into large blocks for storage. These cotton bundles are then transported to the cotton gin, a machine that pulls out the seeds from the cotton bolls.
Wars have taken place since the beginning of recorded history, and they surely occurred before that as well. A war begins when one group of people (the aggressors) tries to force its will on another group of people, and those people fight back. War frequently springs from the differences between people, or from the desire of one group to increase its power or wealth by taking control of another group’s land. Often the aggressors feel that they are superior to the group they want to dominate: they believe that their religion, culture, or even race is better than that of the people they wish to defeat. This sense of superiority makes them feel that it is acceptable to fight to take the land, possessions, and even lives of the “inferior” group, or to force their ways on the dominated people.
Because countries can be very different from one another in government, religion, customs, and ideology (ways of thinking), it is not surprising that nations disagree on many things. But great efforts are usually made to settle the disagreements through discussion and negotiation—a process called diplomacy—before they result in anything as destructive as a war. War usually occurs when diplomacy fails. Because science and technology have allowed us to create such powerful and destructive weapons that can result in such devastating wars, we now have international organizations that work all the time to try to keep peace among nations.
The red carpet treatment dates back to the 1930s, when a carpet of that colour led passengers to a luxurious train, the Twentieth Century Limited, which ran between New York and Chicago.
The Twentieth Century was the most famous in America and was totally first class with accommodation and dining car menus that were considered the height of luxury. Walking the red carpet to the train meant you were about to be treated like royalty.
1. We should never put anything in or near our eyes, unless we have a reason to use eye drops. We would only do that if our doctor or parent told us to use them.
2. If the lens in our eye doesn’t work quite right, we can get glasses to help us see. Glasses have lenses in them that work with our eye’s own lens to help us see better.
3. Just behind the pupil is a lens. It is round and flat. It is thicker toward the middle.
4. Over the front of our eye is a clear covering called the “conjunctiva.”
5. Blinking helps to wash tears over our eyeballs. That keeps them clean and moist. Also, if something is about to hit our eye, we will blink automatically.
6. Some people start to sneeze if they are exposed to sunlight or have a light shined into their eye.
7. The highest recorded speed of a sneeze is 165 km per hour.
8. Our eyes have many parts. The black part on the front of our eye is called the “pupil.” It is really a little hole that opens into the back part of our eyes.
9. Our body has some natural protection for our eyes. Our eyelashes help to keep dirt out of our eyes. Our eyebrows are made to keep sweat from running into our eyes.
10. The most common injury caused by cosmetics is to the eye by a mascara wand.
11. It is impossible to sneeze with your eyes open.
12. Around the pupil is a colored muscle called the “iris.” Our eyes may be BLUE, BROWN, GREEN, GRAY OR BLACK, because that is the color of the iris.
13. Our eyes are very important to us, and we must protect them. We don’t want dirt, sand, splinters or even fingers to get in our eyes.
14. The reason why your nose gets runny when you are crying is because the tears from the eyes drain into the nose.
15. The space between your eyebrows is called the Glabella.
16. The white part of our eye is called the “sclera.” At the front, the sclera becomes clear and is called the “cornea.”
17. We don’t want our eyes to get scratched or poked. That could damage our sight!
18. Babies’ eyes do not produce tears until the baby is approximately six to eight weeks old.
19. Inside our eye, at the back, is a part called the “retina.” On the retina are cells called “rods” and “cones.” These rods and cones help us to see colors and light.
20. Your eyes blinks over 10,000,000 times a year!
21. The study of the iris of the eye is called iridology.
22. The shark cornea has been used in eye surgery, since its cornea is similar to a human cornea.
23. The number one cause of blindness in adults in the United States is diabetes.
24. The eyeball of a human weighs approximately 28 grams.
25. The eye of a human can distinguish 500 shades of the gray.
26. The cornea is the only living tissue in the human body that does not contain any blood vessels.
27. The conjunctiva is a membrane that covers the human eye.
28. Sailors once thought that wearing a gold earring would improve their eyesight.
29. Research has indicated that a tie that is on too tight cam increase the risk of glaucoma in men.
30. People generally read 25% slower from a computer screen compared to paper.
31. Men are able to read fine print better than women can.
32. In the United States, approximately 25,000 eye injuries occur that result in the person becoming totally blind.
33. All babies are colour blind when they are born.
34. A human eyeball weighs an ounce.
Just as telephones are connected by a worldwide phone system, home and work computers can connect with a global computer communications network known as the Internet. Each computer that is linked to the system has its own Internet address, as individual as a phone number. Home computer users buy the services of an Internet provider, which is an organization with powerful computers that link all its subscribers to the Internet.
Many large organizations and companies have computers that link them directly to the network. Internet users can visit the World Wide Web, which is a global network of Web sites providing information, entertainment, products, and other services.
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.