Karen Hill

You would have to be in an airplane looking down on the Nazca Desert in order to see this Peruvian puzzle. A series of gigantic pictures and designs have been made by removing the dark topsoil and exposing the lighter yellow soil underneath. The subjects are flowers, spiders, birds, snakes, and gods wearing halos. Some … Read more

At Stonehenge in England stand huge stones, some as high as 24 feet, arranged in three circles, one inside the other. They seem to be in that pattern for a reason, but until only recently, no one knew that reason. People could only guess that it was an ancient temple, which, according to radiocarbon tests, … Read more

Easter Island, a volcanic island in the South Pacific, is the site of a great mystery. Over 600 enormous stone heads, 2,000 years old, each carved from a solid piece of rock and with identical faces, stand over all the island. They rise from 10 to 40 feet above the surface and weigh up to … Read more

Machu Picchu, in Peru, is called “The Lost City of the Incas” lost, because it was only discovered in 1911. The temples, palaces, stairways, and terraces of this ancient walled Inca city show that its people worshipped the sun and were amazingly accurate as astronomers. One of the temples is so arranged that a wall … Read more

The ancient Egyptians buried their royalty in pyramids under millions of tons of rocks because they believed this would assure them of a life of peace and wealth after death, and an eternal life for their souls. The largest pyramid ever built, the Pyramid of Cheops, or the Great Pyramid, in Giza, Egypt, was probably … Read more

The ancient people of Egypt, Greece, and the Near East all had legends about imaginary creatures with human heads and animal-like bodies. These people built statues of these creatures, called sphinxes, to guard their temples and tombs. The sphinx in Greek mythology had the head of a woman and the body of a lion. She … Read more

Although people enjoy the custom of kissing under the mistletoe, this plant has another, not so pleasant habit. Just as a vampire sucks the blood of its victims, the mistletoe has a victim too, the plant on which it lives. In order to get nourishment, the mistletoe plant sends its root like structures into the … Read more

The small scarlet, white, or purple flowers of the plant called the scarlet pimpernel can give you a better weather prediction than the radio or TV weatherman. If you are in the woods in the morning and you see the flowers on this herb close up, you will know that rain or cloudy weather is … Read more

How about as tall as a ten-story building! Yes, there is a grass that grows that tall. It is called bamboo and grows in tropical areas. Even though these woody poles are so tall and so hard, they are actually in the same family as the grass in your yard. Some bamboo grows at an … Read more

The unusual baobab trees of Africa have trunks so wide, often approaching 35 feet in diameter that entire native families live in them. These trees are second in size only to the giant sequoias of California, but they have such a soft pulp inside their trunk that they can easily be hollowed out and used … Read more

Trees grow up because that is where the light is, and they need the light in order to continue growing. Like most plants, trees grow from seeds and have roots, stems, and leaves. A seed sends its roots down into the ground when it begins to grow, to take minerals and water from the earth … Read more

The Bible tells of two sacred trees in the Garden of Eden, the Tree of Life and the Tree of Knowledge. Adam and Eve were permitted to eat the fruit from any tree in the Garden of Eden except the fruit from the Tree of Knowledge, since God did not want them to have the … Read more

In the Methusaleh Grove, high on the windswept White Mountains near Bishop, California, grow the oldest living things on earth, over 4,000 years old. These are the bristlecone pines, also known as “living driftwood” because of their gnarled and bent appearance. The bristlecone pine is a bushy evergreen that got its name from the long, … Read more

The rubber belt is a name given to the area where the hevea, or rubber tree, grows. This tree needs a very rich deep soil and a climate that is hot and moist. Those are exactly the conditions about 700 miles above the Equator and 700 miles below it. These ten degrees of the Equator … Read more

Rubber comes from a milky white juice which some trees and plants have instead of sap. This liquid, called latex, can be found in the roots, stems, branches, bark, leaves, and fruit of over 400 different plants. Most latex, however, comes from the inner bark of the hevea, or rubber tree, of Brazil. To get … Read more

The smells in flowers come from special oils that are produced in the petals as the plant grows. When this oil evaporates, which it does very easily, it gives off a fragrance which we can smell. Various combinations of chemicals in the oils of different flowers result in a variety of fragrances. Some are pleasant, … Read more

Many flowers have petals which are open during the day, but which close up at night. These flowers are reacting to light or temperature changes. Other flowers, however, remain open around the clock, while still others have unusual opening and closing habits. But these habits are all related to light or temperature changes. Here’s how … Read more

Cactuses are thrifty plants that live in dry regions. They may not get much moisture where they live, but they manage to make the most of what they do get. Since the cactus’s long roots lie close to the surface of the ground, they can catch water from desert rains. And since the roots have … Read more

The meanest kind of plant life is the strangler tree, which comes in several varieties. One example is the strangler fig tree of Brazil, whose fruit provides food for native birds. Once a bird has eaten a fig, it may fly off with the fig seed in its mouth. It often deposits that seed at … Read more

Someone lost in a forest need only study the trees around him carefully to find his way. In our hemisphere, he will find that the side of the tree with the most leaves and branches is the south side. Also, by checking the tops of the trees, he will find that they lean to the … Read more

Some plants depend on animals such as birds or insects to carry their seeds away to start new plants; others just drop their seeds onto the ground about them, and new plants soon sprout, or are carried to other locations by the wind. But a number of plants, like the squirting cucumber, have a strange … Read more

The beautiful water hyacinth, with its ten-inch lilac flowers, is just too much of a good thing. This floating plant has roots which hang freely in the water, as opposed to other water plants whose roots are imbedded in the mud. In just one season, a single piece of a floating root can start off … Read more

The blue moonwort, a member of the primrose family, can. It grows on the Swiss Alps, where it is covered by several feet of ice and snow throughout the winter. This does not seem to discourage the moonwort at all. With the coming of spring, the moonwort’s roots drink up a bit of water from … Read more

Although we use tomatoes as vegetables, they are actually classified by botanists as fruits because they contain seeds inside their juicy, pulpy tissue. In fact, the tomato is considered to be a berry, much like the strawberry, blackberry, and raspberry. Aside from tomatoes, several other foods that we usually term vegetables are considered fruits. These … Read more

Leaves are actually little “factories” that manufacture food to help the plant grow. In the spring and summer, these factories run at top speed, taking in carbon dioxide from the air and water from their roots. Then sunlight enters the leaf and sets the factory in motion. But a leaf could not begin its manufacturing … Read more

Most trees begin life as a seed and continue to grow as long as they live, some for hundreds or even thousands of years. The history of a tree, its age, plus events that took place as it grew, can all be revealed by studying its trunk after it is cut down. A tree grows … Read more

Far from it! In addition to the obvious poison mushrooms, poison oak, and poison sumac, there are about 700 other poisonous, or toxic, plants which are usually avoided by people and animals. Common garden shrubs and plants such as azaleas, rhododendrons, mountain laurel, and foxglove are completely poisonous. There is cyanide in cherry twigs and … Read more

Poison ivy is a vine that straggles over the ground or winds itself around tree trunks, or even forms its own bush if it has nothing to wind itself around. The poison ivy leaf is made up of three leaflets. These leaflets contain poisonous oil that irritates the skin of anyone touching them. This oil … Read more

Yes! Plants which trap and eat insects and other small animals are called carnivorous, or meat-eating, plants. These carnivorous plants are usually found in areas where the soil does not have a good supply of minerals to nourish the plants. So the plants get these needed minerals from living victims, usually by digesting the soft … Read more

In the South American country of Venezuela, in a huge, thick, “lost” rain jungle sit several mesas, high, flat-top plateaus with steep sides. These mesas are in such a remote area of the jungle that it takes four days of travel by water to reach them from any settlement. One of these mesas, called Auyan-tepui, … Read more

Most things get a little bigger when they are heated, even though you probably cannot notice it. If you were to place a glass in a pan of water and heat the water slowly, all the surfaces of the glass would expand evenly, making the whole glass a little bigger. But if you pour boiling … Read more

Have you ever gone camping in the mountains and heated water over an open fire? If so, then you probably discovered that the water boils much more quickly at the higher altitude than at sea level, but at a lower temperature. The one thing that determines the boiling point of water, no matter where you … Read more

There is no record of it ever having rained cats and dogs, but it has rained FROGS. How can this happen? A whirlwind passing over a river or lake, where frogs mate, may scoop up their fertilized eggs and carry them along in the air for a distance. While the eggs are being whirled along … Read more

No. Dark, dirty snow absorbs the heat rays of the sun more quickly than clean, white snow, which reflects these rays back into the air. So dirty snow melts faster than clean snow. Actually, clean snow isn’t white at all. The tiny flakes are frozen, colorless ice crystals which reflect the light and make the … Read more

When you are in a warm house and it is cold outside, you probably have seen the windows steam up. At one time or another, you also probably took your finger and drew a picture on the window and found that your finger came away wet. And did you ever wonder why? Did you wonder … Read more

Since the moon’s mass (the amount of matter it contains) is smaller than earth’s, the moon has a weaker gravity pull, only one-sixth the pull of earth. This means that everything is six times lighter on the moon than it is on earth. A person weighing 120 pounds on earth would weigh only 20 pounds … Read more

First, there was the challenge of the unknown. We have always had explorers of new frontiers who wanted to find out “what’s out there.” Second, these trips have led to the discovery of important information about ourselves. Preparing an astronaut for weightless travel has taught us much about the human body, that man can work, … Read more

Even though there is no air, no wind, and no water on the moon, that is not the major problem in building a moon city. Neither is the engineering that great a problem. The real problem in colonizing the moon is its temperature. Here on earth, we are not accustomed to great variations in temperature. … Read more

The ocean’s depth is measured not by looking, but by listening. This is done with a detection device called sonar. Sonar comes from the words SOund NAvigation and Ranging. Sound waves are sent to the ocean floor and their return time noted. Sound travels through water at the rate of 5,000 feet per second, so … Read more

Just as your parents today might put a fence around your property to keep out unwanted guests or animals, Emperor Shih Huang Ti built a wall to keep out China’s enemies in 221 B.C. But his wall, the longest in the world, was 1500 miles long, or about the distance from New York City to … Read more

All mountains were formed through very slow movements of the earth’s crust. These changes produced four different kinds of mountains, depending on how the crust reacted to these movements. If the earth’s crust formed waves, or upfolds and downfolds, much like an accordian, and layers upon layers of rock pressed on each other, they formed … Read more

When flowing water hits against any kind of barrier, it twists away and spins around rapidly with great force. This creates a whirlpool. Whirlpools can occur in a small area where a piece of land juts out into a river, causing the water to swirl around. They can also occur in the middle of the … Read more

The colorful stone “icicles” which hang from the roof and walls of some caves are called stalactites, and those rising from the floor are called stalagmites. Both these formations build up when water drips through rocks in a cave roof. These rocks contain mineral deposits called calcite. It is this calcite and other minerals which … Read more

The deep, fine sand we call quicksand forms on sand flats at the shore or at the bottom of streams or rivers which flow on top of bases of clay. The smooth, rounded grains of sand slide past each other in wavy movements called swells. This movement is created because the water has no place … Read more

Fossils are the remains of prehistoric plants and animals which were buried in the earth before they decayed and have been preserved in any of several ways. Petrified fossils, those turned to stone, include bones of animals and wood of plants. As they lay in the earth, they filled with minerals and became solid and … Read more

Coal was formed from the remains of ancient, strange looking trees, giant ferns, soft mosses, and grassy plants, all of which grew in swampy jungles hundreds of millions of years ago. When these giant trees and plants died and fell into the swamp, they rotted and became mixed with other decaying plants, forming a spongy … Read more

The Dead Sea, on the border between Israel and Jordan, is really a lake, fed from the north by the Jordan River. Although the Jordan pours 4,740,000 tons of fresh water into the Dead Sea each day, that fresh water evaporates very quickly because of the extreme heat in this part of the world. The … Read more

Caves, or caverns, are holes made in the earth’s surface by the forces of nature. Sea caves were formed by the steady beating of the sea against large rocks on shore. This beating, over thousands of years, hollowed out a cave. The Blue Grotto on the Isle of Capri in Italy is probably the best-known … Read more

Springs form when rain water gets into rocks through cracks. Gravity pulls it down until it finds an opening in the ground in a low place. The spring water escapes through cracks in the rocks along these low places. As it passes through the rocks, the water picks up minerals, which some people consider health-giving. … Read more

Ordinary light seems white as it shines, but it is actually a combination of colors, violet, indigo, blue, green, yellow, orange, and red. Any time the light gets broken up, as in a soap bubble, an oil puddle, a piece of cut glass, or a diamond, we see all or most of these colors. In … Read more

To answer that question takes a lot of “ifs.” If the earth were completely dry, with no oceans separating continents, you, as a person, could walk around our planet, traveling day and night at a steady pace, in less than a year. If, however, you were a tidal wave, you could cross the earth in … Read more

A volcano erupted on August 27, 1883 on the tiny Indonesian island of Krakatoa in the South Pacific. The eruption was so powerful that it caused a tidal wave, or huge wall of water, as tall as a 9-story building. The wave wiped out 163 villages on Krakatoa, killing 36,380 people. It even washed ashore … Read more

In order to avoid airplane collisions because of all the air traffic over our big cities, the sky is carefully mapped. It is actually divided into highways, or airways, which are numbered and have speed limits. As a kind of road sign, radar signals from control towers at check points along the route are beamed … Read more

Man’s deepest journey to the center of the earth was made by a petroleum company in Texas. The hole was dug in search of oil, but when none was found, the hole was plugged. However, drillers worked for two years, at a cost of 3 million dollars, to reach a depth of 25,340 feet, or … Read more

Since the earth is suspended in space, it cannot be put on a scale and weighed. But scientists can estimate its total weight by estimating the weight of each of its parts, the crust, or solid rock, the mantle, also solid rock, and the core, a liquid, because of the great heat at the center. … Read more

What! In the driest place in the world? But the answer is yes! In places like the Sahara Desert in Africa, people can fish in the many underground streams which lie on top of a layer of clay beneath the sand. The water feeding these streams comes from nearby mountains where rain does fall. This … Read more

When a glacier, or river of ice, reaches the sea, a piece of it often breaks off, falls into the sea, and floats. These broken-off pieces of glaciers are called icebergs. Icebergs come in all sizes, from 20 feet across up to 200 miles across. Some icebergs rise as high as 400 feet above the … Read more

When you live in a place like Siberia, in northern Russia, you know what cold means. Ice and snow cover this area for half the year. This is the place of the lowest temperature ever recorded, 90° below 0° Fahrenheit. It is not a good place for people who enjoy outdoor sports. Five minutes outdoors … Read more

Snow is actually water vapor that has frozen in the clouds into shimmering six-sided ice crystals. These ice crystals appear white instead of colorless, as does water, because all the sides of the little ice crystals that make up a snowflake reflect light. The amazing thing is that although billions of snowflakes fall in a … Read more

Most glaciers move very slowly, usually less than a foot a day, although some have been known to move more than 50 feet a day. However, different layers of one glacier also move at different speeds. The bottom moves slowly because it is rubbing against the land, while the middle and top move more quickly … Read more

Scientists studying glacial ice in Greenland drilled down 4,550 feet and concluded that the glacier was formed 2,000 years ago. But that is pretty “new” ice if you compare it with the glaciers in Antarctica. These glaciers are estimated to have formed about 90,000 years ago, and have remained frozen since then! About 250,000 years … Read more

The huge masses of ice flowing slowly over land are what we call glaciers. They form in high mountains and in polar regions, where large amounts of snow build up and freeze into ice. Snow falls in these places during the winter, but not all of it melts in the summer. The remaining snow builds … Read more

Water moves continuously through the ocean in huge rivers called currents. Currents may flow on the surface of the ocean, where they are shallow, or they may flow far below the surface, where they are deeper. Ocean currents are set in motion by the wind. The rotation of the earth moves them clockwise in the … Read more

Fresh water is necessary for human life because it dissolves the nutrients we eat and carries them through our body in the processes of digestion and absorption. Fresh water also helps regulate body temperature. We cannot drink sea water for two reasons. First, the bacterial count may be too high for our health. The second … Read more

The Bay of Fundy, which separates both Maine and New Brunswick from Nova Scotia in Canada, has the highest tides in the world. They rise and fall anywhere from 10 to 60 feet in an hour! The energy generated by these tides is so great that Canadian engineers are talking about building a dam on … Read more

If you have ever spent time at the beach, you probably noticed that the water rises slowly on the shore for six hours, then slowly recedes, or falls back, for another six hours. This movement, which happens twice a day, is called tides. Tides are caused by the pull of the moon when it is … Read more

Dr. James Van Allen, an American physicist, had been studying space satellites for many years, and in 1958 he came to the conclusion that the reason life on earth is not destroyed by radiation from the sun is due to two belts that surround the earth. These belts, named after Dr. Van Allen, are actually … Read more

A greenhouse gives plants a glass covering which serves two purposes: it conserves the energy they get from the sun and it keeps the air temperature up. The atmosphere surrounding our planet acts the same way. Only a tiny fraction of the heat and energy produced by the sun ever reaches the earth. And that … Read more

Even though you might think you are standing still anywhere on earth, you are actually moving in five directions, all at the same time! First, the earth is continuously rotating on its axis, which gives us day and night. Second, the earth is continuously orbiting the sun, traveling 600 million miles a year, at a … Read more

The top of Mt. Everest in the Eastern Himalaya Mountains on the border between Tibet and Nepal takes honors as the highest place on earth. Everest rises 29,028 feet, or 5.5 miles, above sea level. Attempts have been made to climb Mt. Everest since 1921, but it wasn’t until 1953, after eleven men had died … Read more

Although the highest mountain peaks have been climbed and the densest forests have been visited, there are still about 140,000,000 square miles of unexplored area on earth. Those miles are found on the ocean floor, with its winding valleys, towering mountains, steep canyons, and vast plains. On land, there are still some remote areas that … Read more

Geysers are underground springs which spout up columns of steam and boiling water from time to time. They form when cold water finds its way from the surface of the earth deep into the rock below. As the water travels, it finds a crack in the rock or wears away a crevice to make its … Read more

There are four basic “ingredients” that go into the “recipe” for making soil: tiny pieces of rock, decayed plants and animals, water, and air. When small pieces of rock break off larger ones, they form the basis of all soil. This breaking can occur in several ways: through the action of glaciers pushing rocks along … Read more

Fog, like clouds, is a collection of water droplets, dust, and ice. Since city air has more dust and soot from factories, chimneys, and traffic, city fogs are thicker than country fogs. London, the city long famous for its incredibly thick “pea-soup” fogs, enacted antipollution laws which actually decreased its fog problem!

Fog is actually a cloud, but it is a low cloud that lies close to the ground or sea. It is formed when warm currents of air hit against cold air resting above land or water. What happens is that the sudden cooling causes moisture in the warmer air to condense, or form tiny droplets … Read more

No, it doesn’t. Although most substances shrink when they change from a liquid to a solid, this is not true of water. When water freezes, it expands, or gets bigger, actually one-tenth bigger. So nine buckets of water freeze into ten buckets of ice. This explains why water pipes sometimes burst when temperatures are below … Read more

Amazingly enough, whenever you ice skate, you are doing precisely that, skating on water. Here’s how it happens. When the blade of your ice skate touches the ice, it actually is putting the pressure of your body weight on that thin strip of ice. The ice melts for an instant as a result of that … Read more

Our planet has up to 1,000,000 earthquakes every year, but most of them occur on the ocean floor and cause very little or no damage. It is only those which occur on land and near big cities that cause damage and loss of life. There are places which have never had a serious earthquake, the … Read more

The outer layer, or crust, of the earth is made up of plates that are constantly moving past one another in very slow side-to-side and up-and-down movements. These movements cause the earth’s rocks to rub against and slide past each other at their outer edges, creating a break in the crust. This break is called … Read more

No. Each liquid has its own freezing point. Water, for example, freezes at 32° Fahrenheit (0° Celsius). Mercury freezes at a lower temperature, -38° F. (-39° C), a good reason why it is used in most thermometers. Salt water, or seawater, freezes at about 28.5° F. (-1.9° C), lower than fresh water because of the … Read more

Dry ice is the name given to carbon dioxide, a gas, when it freezes into a solid state. Dry ice is used to refrigerate food. It is called “dry” ice because when it melts, it doesn’t melt into a liquid like ordinary “wet” ice does. Dry ice melts into a gas. Foods that have to … Read more

Perhaps you thought that the weather conditions at the Arctic area of the North Pole and the Antarctic area of the South Pole are pretty much alike. Most people think that, but they are wrong. In the first place, the North Pole is mostly water, the Arctic Ocean, with just the edges of the continents … Read more

Hurricanes are violent storms of wind and rain that can hit areas hundreds of miles across. They usually start in the tropics, with warm, moist air rising in a spiral over the ocean. As the air swirls upwards to colder areas in the atmosphere, the water vapor in the warm air cools and turns to … Read more

The weight of air pushing against the earth is what weathermen call air pressure. This weight changes from place to place and from time to time in the same place. These changes are sometimes caused by changes in temperature. When the sun’s heat warms the air, it makes the air currents rise skyward. Since warm … Read more

Although you probably know that liquids and solids have weight, you may not have realized that air has weight too. You can see this weight by taking an “empty” soda bottle, pumping out the air with a small pump, and covering it immediately. Then weigh the bottle. Now, unscrew the cover and let the outside … Read more

When you drop a straw into a bottle of soda, that straw is filled with air. As you put the straw into your mouth and start sucking in, you begin by sucking the air out of the straw, creating a vacuum, or airless space, inside the straw. Since air pressure is at work all around … Read more

When electricity is given off through lightning, it heats the air in its path. This heating makes the air expand quickly and often violently. The molecules of heated air fly around in all directions and collide with cooler, distant air. This collision sets up a “wave” of noisy, rumbling air called thunder.

When Ben Franklin came in from the storm with his key and kite, he brought back some important facts about electricity for all the world. We now know that lightning is an electrical current that flows from one cloud to another, or from one cloud down to earth. The tiny droplets of water in clouds … Read more

Yes, to a very small extent. As the earth rotates on its axis, it wobbles a little because the moon pulls it. This pull is so slight, however, that you cannot feel it, just as you cannot feel the earth rotating. The amount of change in the day’s length will not affect our lives too … Read more