When automobile racing began in the 1890’s, the speed were like those of a fast horse and buggy. The first major race, held in 1895, was from Paris to Bordeaux, France, and back. The winner averaged only24 kilometers (15 miles) an hour. But the speeds of racing automobiles increased every year. By the 1960’s, the racing automobile was nearly as fast as some kinds of airplanes.
Autoracing includes event and classes for almost every kind of four wheeled vehicle. The racing rules and formulas are established so that the vehicles in each classperform as much like the others as possible.
Racing takes place many kinds of tracks. There are oval track, drag strips, and twisting tracks build around oval track. There are also cross-country races on public roads or on the dirt and sand. If a car is designed for one type of track if minor change are made in the car.
The emphasis in automobile racing has shifted away from pure speed. Race car designers now concentrate on improving the cornering speeds, breaking, and furl economy of their machines. Top speeds on a straight course have not increased much since the 1960’s. But racing cars are getting around the track faster. This is because of improvement in tires, design, brakes, and aerodynamic (the study of the way in which air affects moving objects). It can be said, then, that winners of race are determined by abilities of the drivers, the car designers, and the mechanics.
Modern racing cars have been made safer with stout metal frame bars, noneploding fuel tanks, and build-in fire estinguishers. Race courses are now usually lined wth safety barriers to help stop cars that go out of control. Safety helmets and fire proof driving suits provide more protection for the driver. But racing is still a dangerous sport, and the driver must be highly skilled.
The Atlantic Ocean is a huge body of water second only to the pacific Ocean in size. The Atlantic furnishes fine trade routes and fishing grounds for four continents Nort America, South America, Europe, and Africa. It was the first ocean to be crossed by ships and airplanes.
The Atlantic ocean may have been named for the mythical land of Atlantis. According to legend, Atlantis was suddenly swallowed up by the sea and disappeared ages ago. Another legend names the ocean for the Atlantides. These water nymphs were the daughters of Atlas. Their home was the Atlantic Ocean beyond the Atlas mountains.
The Atlantic Ocean has an average depth of about 12,800 feet (3,900 meters). Its bottom is covered mainly with an ooze made up of the shells of tiny ocean animals. The deepest place is in the North Atlantic, north of Puerto Rico. Here in the Puerto Rico Trench, the ocean reaches down 27,510 feet (8,385 m).
The ocean bed of Atlantic isi divided into two valleys by the mid-Atlantic ridge. This is an S-shaped ridge running from north to south and rising about 6,000 feet (1,830 m) from the ocean bottom. Where the ridge rises above sea level, it forms the island of Azores, Saint Payl Rocks, Ascension, Saint Helena, Tristan da Cunha, and Bouvet.
Compares to the fairly straight coast of the South Atlantic, the North Atlantic has a very irregular shoreline. The greatest indentations are on the European side of the ocean. These are formed by the Baltic, Nort, Mediterranean, and Black seas. The coastal waters on the American side include Hudson Bay, the Gulf of Saint Lawrence, the Gulf of Mexico, and the Caribbean Sea. Water from most of the great river systems of the world flows into the Atlantic. These rivers the Saint Lawrence, Mississippi, Orinoco, Amazon, La Plata, Congo, Niger, Nile, Don, Dnieper, Danube, Po, Loire, Rhine, and Elbe give the Atlantic the largest drainage area of any ocean. Such drainage, from about half of the world’s land area, includes many dissolved minerals and makes the Atlantic the saltiest of the ocean.
“Give a place to stand, and I can move the world.” The man who is supposed to have spoken those words was Archimedes, a Greek mathematician and inventor who lived some 2,200 years ago. Its was not and idle boast. Archimedes was one of the firs men to the develop the science mechnics. He understood that a man with a mechanical device such as alever could move many times his own weight. Challenged by the king to prove his point, Archimedes did so. He arranged a ship all by himself.
Archimedes was born about 287 B.C., in Syracuse, a Greek settlement on the island of sicily. Little is known about his personal lefe except that his father was an atronomer and may have been related to the king of Syracuse. Also, at some time in his life Archimedes studied in Alexandria, Egypt, a center of Greek culture.
Archimedes is best known for his many inventions. Among other things, he invented a compound pulley; a sphere that imitated the motion of heavenly bodies; and a water screw to raise water. He himself moast valued his work in mathematics and scientific theory. But his fame rest on inventions and the legends that grew up around him.
One legend tells how Archimedes made his most important discovery.
The king, it seems, had ordered a new crown. It was supposed to be made of solid gold, but the king suspected that the jeweler has cheated him. He asked Archimedes to tell him if the crown was solid gold.
At first Archimedes could not think how to do this. Then one day the solution came to him as he was getting into his bath. Legend has it that he ruhed naked into the streets shouting, “Eureka [I have found it]!”. 
What had happened very simple. The bath was full, and it overflowed as Archimedes climbed into it. This started him thinking about the way objects displace water. And he studdenly saw how to solve his problem.
First he took a quantity of gold and silver were equal, but their volumes were not. The silver, being less dense, was bulker than the gold.
Next Archimedes two vessels filled to the brim with waqter. He palced the gold in one and the silver in the other. The silver, being bulkier, caused more water to overflow. Archimedes concluded that when a solid sinks in water, it displaces its own volume of water.
Finaly he tested the crown against the equal weight of gold. When placed in water, the crown caused more overflow. Therefore, the crown had to contain metal other than gold. This metal made it bulkier and caused the greater overflow.
Further experiments resulted in what is known as Achimedes’ principle ; An object in a fluid is buoyed up by a force equal to the weight of displaced fluid.
When Archimedes was an old man, the Roman attacked Syracuse. He turned his mind to defense, an inveted several engines of war that held off the enemy. It is claimed that he built a huge burning mirror. When it was used to focus the sun’s rays on the roman fleet, the ships were set on fire. Syracuse however, was defeated in 212 B.C., and Archimedes was killed. The story goes that he was drawing mathematical figure in the sand when Roman soldier struck him down. Archimedes was so higly respected that the Roman commander buried him with full honors.
The apple, often called “the kings of fruits,” is the most important tree fruit of the temperate regions of the world. Apples have been grown and used as food since the dawn of history. Cahrred remains found in stone age lake dwellings in central Europe show that prehistoric man ate apples. There are carvings of apples on ancient tombs and monuments in the Near East.
The apple appears often in the myths and folklore of ancient civilization. In greek mythology Hercules traveled to the end of world to bring back the golden apples of the Hesperides. The apple of discord the prize in a beauty contest caused a quarrel between the gods that led to the Trojan War. A Norse myth tells of magic apples that kept people young forever. The Halloween gane of dipping for apples had its beginning among the Celtic peoples of Britain, as a way of foretelling the future.
Apples were brought to America by the earliest European settlers. At first apples were used mainly for cider, which was a popular beverage in England and northern France, where most of the early colonist came from. (cider another name for apple juice that has fermented. It contains a small percentage of alcohol-about as much as beer).
As the frontier moved westward, apple tress followed it. One of the first things settler attended to after the land was cleared and the cabin raised was planting a few apple tress in the yard.
Origin of the apple
Although there are numerous kinds of wild, or crab, apples native to different part of the world, the kind from which the familiar cultivated apple developed came from the mountains of southwestern and central Asia, between the regions of the black and Caspian seas and eastward from there. This ancestor of the modern aplle, which still grows wild, is smaller and more sour than our present fine varieties, but the tree on which it grows resembles our present cultivated trees.
People selcted the best fruit from the wild trees for eating and used seed from the better fruit for planting. In this way quality of apples was gradually improved.
Uses of apples
Apples have many uses. They are eaten fresh, cooked, dried, and canned. Their juice is used for drinking and making vinegar. Aplles furnish valuable minerals and vitamins and add bulk to the diet. Fres apples help clean the teeth and reduce tooth decay.
Almost 49,000,000 metric tons (160,000,000 bushels) of apples are produced each year in commercial orchards in the United States alone. About 60 percent of the crop is sold as fresh fruit. The rest in canned commercially as applesuece and sliced apples, is frozen, or is crushed and pressed for apple juice or vinegar. Apple pie is a favorite dessert in United State and Canada.
The Andes from the longest and one of the highest mountain ranges in the world. Only the Himalayas in south central Asia are taller and more rugged. The Andes Cordillera along the west coast of South America, From the Caribbean Sea in the north to Tierra del Fuego, an Archipelago at the southern tip of South America. The Andes are in every South American Republic except Barzil, Paraguay, Uruguay, and Guyana.
Within the Andean regions are many different kind of life and lands. There are great modern cities and small Indian villages where people live much as they did centuries ago.
There are dense forest and barren plains, fertile farmland, and stony soil where little grows. About a third of all the people in South Aemerica live in the Andean regions. Most of them in crowded cities and towns. For South American capitals lie high in the Andes-Caracas, Venezuela; Bogota, Colombia; Quito, Ecuador; and La Paz, Bolivia.
Many peaks in Andes are over 20,000 feat high-taller than any peaks in North America. Aconcagua (22,835 ft), in Argentina, is the highest mountain in the Western Hemisphere. Many of the Andean Mountains are volcanic. Some are inactive, although a number of them still erupt from time to time and cause great damage.
The northern Andes lie in Colombia, Venezuela, and Ecuador. Much of South America’s fine coffee is grown on the lower slopes of the northern Andes.
The central Andes are in Bolivia, Peru, northern Chile, and northern Argentina. The mountain in some part of central Andes are extremely high and wide, making transportation difficult. For example, to reach La Paz, Bolivia, the railroad must cross the mountain at an elevation of nearly 14,000 feet.
The southern Andes, at the tip of the continent in Argentina and Chile, are the lowest range. This is sparsely populated area.
Many of the people of who live in the Andes of Bolivia, Peru, and Ecuador are the descendants of the ancient Incas and other Indians who inhabited the area before the Spanish conquest in the 16th century. Many of these people still speak an Indian tongue, such as Quechua. The Spanish languange is unknown to them.
The Andes act as a great barrier to transportation and communication. From the Caribbean Sea to the Strait of Magellan there are few passes through the mountains. Deep gaorges, step slopers, and towering heights make roads and railroads difficult and costly to build. Within recent years, however, the airplane and some modern highway have opened up areas that were previously cut off from the outside world.
Two major river system of south America the Amazon and the Arinoco begin in the Andes, High in the mountains beetwen Bolivia and Peru is Lake Titicaca. It is the largest lake in South America and the highest large lake in the world.
The climate in the Andes change with the elevation above sea level. At the lowest elevation, below 3,000 feet, the climate is tropical. Here are dense green jungles and rivers filled with crocodiles. This is called the tierra caliente, or “hot land”.
The climate is cooler from 3,000 feed to 7,000 feed. At 7,000 feet the cold land, or tierra fria, begins. Evergreen trees and wheat grow well at this elevation.
Between 10,000 feet and 13,000 feet is the puna. Only potatoes and barley and a few other hardly crops will grow on these high mountainsides. The top level, between the puna and the snowfields, is called paramo. Nothing grows here except mosses and lichens.
The mines of the Andean regions provide the world with many important minerals. Among them are cooper, tine, and proteleum. Gold and silver re mined is smaller amounts. The supply of coal is limited in most areas.
Many interesting animals live in the Andes. There are llamas, guanacos, alpacas, and vicunas – all members of the camel family. The chincilla is highly prized for its valuable fur. There is the fierce cougar, or mountain lion, and the small deer, or guemal. Tiny humming birds, brilliantly colored, dart about in the Andean forests. Soaring high above the towering, snowcapped Andes are the huge condors, the largest of the vultures. They are also the World’s largest flying birds.
The Amazon is South America’s most important river. A Spaniard named Francisco de Orellana made the firs explorations of theriver in 1541. The Amazon carries more water than the Mississippi, the Yangtze, and Nile together. In a single second Amazon pours more than 60,000,000 galons of water into the Atlantic Ocean. The muddy river stains the ocean brown for 200 miles. This tremendous flow is caused by heavy tropical rains and melting snow in the Andes mountains. The Amazon’s huge basin extends for about 2,700,000 square miles.
The Amazon is almost 4,000 miles long. It begins in the snow-fed Andean lakes of peru, 18,000 feet above sea level, and then flows eastward across the low paliants of Brazil. On its journey the Amazon gathers additional water from hundreds of rivers. The Negro, Madeira, Purus, and Jurua are majaor branches, each one is beetwen 1,000 and 2,000 miles in length.
The Amazon is only 200 feet above sea level at the Peru-Brazil border. It flows slowly on its lenghthy journey to the Atlantic. Sometimes the river is so wide that one cannot see the opposite shore. During the rainy season the flood water spread for miles over the jungle lowland. It is no wonder that the Amazon is sometimes called the River Sea.
Where the river empeties into the Atlantic Ocean a strange thing happens. Twice a day, when tide rises, 12-foot tidal waves called “bores” rush upstream. The current of river is reversed for as much as 400 miles.
Ocean-going ships can travel 1,700 miles up the Amazon from Belem, Brazil, at the river’s mouth. Smaller steamers can reach Iquitos, in Peru, 2,300 miles inland. Ships paa trought some of the most densely forested land in the world.
Around A.D 1100 an unknown alchemist, probably in souther Italy, destiled some wine. He got a clear, colorless fluid with a strange odor. Through this strange new fluid looked like water, it did not behave new at all like water. It had a burning taste. When it wa drunk, it had powerful intoxicating effects. Strangest of all, it burned with a hot, blue flame. This mysterious “burning water,” which the alchemists believed was the spirit of wine, was ethyl alcohol.
Today hundreds of different alcohols are know. Some are clear, colorless fluid that mix freely with water. They evaporate quickly in open air. They have low freezing points. Ethyl alcohol freezes at about –1170C (-1790F). Other alcohols behave quite differently. They are thick, oily fluids that hardly mix with water at all. Some are even solid at room temperature.
Alcohols are made up of atoms of carbon, hudrogen, and oxygen. The carbon atoms from kind of framework around which the hydrogen and oxygen atoms are arranged.
In industry, alcohols are used as raw materials for making many other chemicals. They are also used to dissolve fats, oils, and may organic (carbon containing) substance, include some plastic. Another use is to extract flavoring oil, perfumes, and drugs from plant and animal materials. Some alcohols are burned as fuels in rockets. Scientists are testing the use of alcoholic fuels in automobiles and other land vehicles.
In the home, ethyl alcohol is found in antiseptics, flavorings, perfumes, and liquor. Colored red for visibility, it is used as the fluid in outdoor thermometers. Isopropyl alcohol is used as rubbing alcohol.
All the alcohols exept glycerol are more or less poisonous. Methyl alcohol (wood alcohol) is extremely poisonous, and even a small amount can couse blindness or death. Denatured alcohol is ethyl alcohol that has been made undrinkable by adding poisons or unpleasant-tasting chemicals to it.
Wherever you go, whatever you do inside, outside, on top of mountain, deep in a coalmine you are always surrounded by a sea of gases. This sea is called the air, or the atmosphere.
The gases of the atmosphere cannot be seen, and we are rarely aware of them. But they are of the greates importance. Without the atmosphere, people, animals, an plat could not live. Of almost equal importance is the quality of the atmosphere whether it is pure or polluted (meaning impure).
The atmosphere is made up mainly of the gases oxygen and nitrogen, together with water vapor and smaller amounts of carbon dioxide and other gases. But all air contains small amounts of impurities. In rural areas, far removed from factories and heavy traffic, the air my countain pollen from plants, dust from the soil, and even bacteris. These impurities are usually is such small amounts that they are not important.
Air is said to be polluted when it contains enough harmful impurities to effect the helath, safety, or comfort of living things. The impurities, or pollutans, could be tiny particle of matter or gases not normaly found in air.
When people breathe, pollutans in the air may be deposited in the lungs or absorbed into the body. And polluted air can harm animals and plants as well as people. For this reason, our air supply should be closely watched and managed to assure its good quality.
In 1900 there wa very little people could during a hot spell except grumble about the weather or – if they could afford it-go away to the mountains or the seashore. Today air conditioning has changed this. With air conditioning you can be comfortable any where indoors on oven the hottest, stickest day of the year. You will almost certainly find air conditioning in the movie theates you attend., in many of the stores where you family shop, an in the restaurant where you eat. It may even be ini your own house.
What is Air Conditioning?
You know that air conditioning make you feel cool. But air conditioning is more than just cooling. It means keeping the temperature and humidity (moisture content) of airin an enclosed space, weather it is one room or an entire building, at just the right level for the comfort of the people inside. It alse means circulating the air with fans and removing dust from it with filters. In winter it means heating the air and adding moisture if necessary. In summer it means removing moisture by passing the air over cold pipes that collect water from the air, much as drops of water condenses on a cold water glass on a hot, damp day. In fact, we might almost say that air conditioning means creating an artificial, comfortable climate. In this article we shall discuss only cooling.
In dry vlimates air can be cooled simply. The cooler may be no more than a large fan that draws hot, dry air trought a water soaked fiber mat. The air is cooled as it evaporates the water. It is so dry to begin with that the added moisture will not couse discomfort.
How does air conditioning work? 
An air conditioning unit does not “add coolness” to the air. It removes heat. An air conditioner work on the same basic principle as a refrigrator-though it is not designed to produce such low temperatures. Heat is taken from the air by the rapid expantion of a refrigerant (cooling subtance) as it turns from a liquid at high pressure to a gas at low pressure. An accompanying illustration show the cycle of operation of a small home type air conditioner. Here the air is cooled directly by the macine. For the sake of simplicity, filters and motors are not shoen in this diagram. In large, central installations, such as those in office buildings and schools, a machine chills water that isi piped to a series of coils. Air from building is drawn over these coils and circulated through the building by blower.
To be partical, an air conditioning unit must be able to maintain a steady temperature. Otherwise people would have turn their units off and on continually as the temperature is maintained by a temperature-regulating device called a thermostat. The tremostat is set at the desired temperature. Itthen switches the cooling unit on off as needed.
The air conditioning system of the future may work by what is know thermoelectricity. A thermoelectric unit is very small and very quiet. It is made up of tiny “couples,” each couple consisting of a pair of semi conductor and connected in parallel to an electric current. These couples produce cooling at one end and heating at the other when direct current flows trough them. This is called the peltier effect. When a way is found to produce these tiny thermoelectric unit cheaply. They may cool abd head your whole house.
The abacus is a simple calculating machine that is used for doing arithmetic. A modern abacus is made of beads, rods, and a frame. The rods are fastened in the frame, and each stand for a place in the decimal system. One rod stans for units, one for 10’s, one for 100’s, and so on. The beads are counters. Numbers are added or subtracted by moving the beads on the rods.
The numeral of ancient times were very awkward for doing arithmetic. The trouble was that they did not express zero of place value.
This system of numerals made written arithmetic very difficult. So the romans, like other ancient peoples, used the abacus. The idea of place was built into the abacus. One counter could be made to express 1, 10, or 100, according to its place on the abacus.
Thw abacus offered a quick and easy way of adding and subtracting. It could also be used for multiplication and division. Multiplication was done by adding equals groups. Division was done by substracting equal groups.
However, it is very simple to make an abacus like those of ancient times. You can draw four lines in sand, dust, or soil and use pebbles as counters. Or yopu can rule heavy lines on apiece of paper or cardboard. Use buttons, bottlecaps. Dried beans, or pebbles as counters.
The lines, from right to left, stand for 1’s (or units), 10’s, and 1,000’s. For example. If you want to express 2,222, you put two counters in each row. If you want to express 2,220, you put two counters in three of rows and none in the units row. Make up some numbers of your own and express them.
Now suppose you want to add 271 and 302. Set up one of the numbers; then set up the second number. A glance at the abacus give you the sum.
This is how to subtract 271 from 394. Set up the large number on the abacus and take away the counters that represent thw smaller number.
