Napoleon Bonaparte: A hero in France

The French called Napoleon Bonaparte “a man of destiny.” A hero in France, Napoleon was hated elsewhere in Europe. Today, Napoleon is remembered as one of the greatest military leaders of all time. He built an empire that covered much of Europe.

Napoleon Bonaparte was born in 1769 on Corsica, an island in the Mediterranean Sea. At the age of 16, Napoleon chose a career in the French army.

In 1789, a revolution began that rocked France. The king and queen were executed. Hungry working people demanded new freedoms. Revolutionary governments in France swept away old laws. They declared war on supporters of the former king. The French Revolution lasted until 1799.

Life in the Alps

The Alps make up the largest mountain system in Europe. They are world-famous for their scenic beauty. The Alps are a region of majestic, snow-capped peaks, deep valleys, narrow lakes, and wide glaciers.

The Alps reach across south-central Europe in a broad arc. They stretch all the way from southern France, in the west, to eastern Austria. Along the way, the mountains cross Italy, Switzerland, and Germany. The Alps form a chain that extends about 750 miles (1,200 kilometers).

Why are Rain Forests important?

Where would you go to find more kinds of plants and animals than anywhere else on Earth? You would go to a tropical rain forest.

Tropical rain forests are home to an amazing number of plants and animals. A patch of tropical rain forest no bigger than a school parking lot can have almost as many different species (kinds) of trees as there are in all the forests of Canada and the United States!

Biologists believe that more than half of the world’s plant and animal species live in tropical rain forests.

A rain forest is a place where there is lots of rain. One kind of rain forest is called a temperate rain forest. You can find temperate rain forests where the weather is cool and mild, and very wet.

A temperate rain forest grows near the Northwest coast of the United States. Just a few kinds of evergreen trees grow there. Most of the world’s rain forests are tropical rain forests with many kinds of trees.

Tropical rain forests grow in warm places near Earth’s equator. The equator is an imaginary line that goes around the middle of the planet. There are tropical rain forests in Central and South America, Africa, and Asia. The world’s largest rain forest is the Amazon rain forest in South America. It is always hot and wet in a tropical rain forest.

Different kinds of plants grow in different layers of a tropical rain forest. The ground in a rain forest is called the forest floor. The soil on the forest floor is very thin and poor. Some plants living there get their food from dead plants. Other plants on the ground eat insects. The pitcher plant is an insect-eating plant that grows in rain forests in Asia.

The plant layer just above the forest floor is called the understory. Not much sunlight gets down to this layer. Young trees and plants that like low levels of light grow in the shady understory.

The top layer of the rain forest is called the canopy. The tops of tall trees make up the canopy. They capture most of the sun and rainwater falling on the forest. The canopy is thick and green.

Between the understory and the canopy is a layer called the midstory. Medium-size trees grow in the midstory. Thick vines climb up, around, and between the trees. Mosses, orchids, and other air plants (plants without ground roots) grow on the midstory trees.

Most of the animals that live in a tropical rain forest are insects. The forest is alive with millions of beetles and ants. Bats and beautiful moths fly about at night. Snakes glide silently in and around the trees. Birds are everywhere.

In Africa, wild pigs, gorillas, and other large animals live on the forest floor. Elephants walk through the rain forests of Asia and Africa. Jaguars hide in South American forests and wait for prey, such as a wild pig, to go by.

Most of the rain forest animals live in the canopy. Monkeys swing from branch to branch in the rain forests of Central and South America.

Rain forests are home to huge numbers of plants and animals. Scientists are discovering new ones all the time. Some rain forest plants are used for medicine. Scientists believe there may be many other plants that could be used to treat cancer and other diseases.

Rain forests are like the “lungs” of planet Earth. The trees take up a gas called carbon dioxide. They give off a gas called oxygen. All animals must breathe oxygen in order to live. Too much carbon dioxide in the air could make Earth grow warmer.

For thousands of years, people have lived in the rain forests. People native to the forests hunt wild animals and collect plants for food. They use certain rain forest plants for medicines.

Today, rain forests all over Asia, Africa, and South America are being cut down. Loggers cut down hardwood trees for lumber. Teak, rosewood, and mahogany make beautiful furniture.

Farmers clear the rain forest to plant crops. But the poor rain forest soil soon washes away. Then the farmers must move and clear more rain forest.

People cut roads through the rain forest to reach mines and oil wells. Lumber companies build roads to haul logs. The amount of rain forest cut down every year would fill the state of Wisconsin!

Conservationists are looking for ways to save the rain forests. Some countries, such as Costa Rica in Central America, have set aside rain forests as national parks.

In other places, poor people need the rain forests for food and wood. Conservationists are looking for ways that people can use the forests without destroying them. People are learning how to grow nuts, seeds, and other crops in the rain forest. They are learning how to make butterfly farms and other places that people can visit on a vacation.

Will the Universe end?

 Look up at the sky on a clear, starry night. What you see is part of the universe. You could never see all of the universe. No one even knows whether the universe has an edge or if it goes on forever. The universe contains all matter and energy. The universe holds all space and time. You are a part of the universe. The universe includes everything there is.

Earth and all the planets in our solar system make up just a tiny part of the universe. Billions of other stars like our Sun all form a group called the Milky Way Galaxy. With telescopes we can see billions of other galaxies. Galaxies are in turn clumped together in enormous groups called clusters and superclusters. There are at least 100 billion that’s 100,000,000,000 galaxies in the universe. The universe is a big place!

The universe holds many strange things, such as exploding stars. It holds great clouds of gas and dust where new stars form. It also holds black holes. Black holes have a pulling force called gravity. Gravity is the force that holds you to the ground and makes things fall when you drop them. Black holes suck in all the matter around them. The gravity of black holes is so strong that nothing, not even light, can escape.

Astronomers think there is even more matter in the universe than we can see. The matter we see makes up gas, dust, galaxies, stars, and planets. Astronomers think there is a type of invisible matter that they call dark matter. They think there may be a lot more of this mysterious dark matter in the universe than there is regular matter that we can see.

Astronomers also think the universe holds a strange substance that they call dark energy. They don’t know much about dark energy except that it seems to make the universe expand.

Many astronomers think the universe began about 14 billion years ago. They think it suddenly exploded into being. They call this beginning the big bang. All space and time began with the big bang. With a special telescope, astronomers can see radiation left over from the big bang. They call this cosmic background radiation.

The big bang theory says that the universe was hotter than you can even imagine at the moment it began. The universe started to fly outward, or expand. As it expanded, it started to cool. Tiny particles that would make up matter started to form. All of this happened in just a few minutes.

When the universe was about 1 million years old, it had cooled to about 5900° Fahrenheit (3300° Celsius). This temperature was still scorching, but it was cool enough that tiny bits of matter called atoms started to form. All the objects around you the computer, the floor, the air are made of atoms. The hot atoms gave off rays of light. The universe was like a huge, hot fireball.

Over millions of years, the force of gravity pulled gas and dust together. Stars and galaxies formed from clumps of gas and dust. The stars began to shine. Our Sun and our solar system formed about 4.6 billions years ago.

Rays of light travel across the universe. Even though light travels extremely quickly, it takes light millions or billions of years to travel from galaxies far away. When astronomers see light from the most distant galaxies they know the light is “old.” They know they are seeing the galaxies as they were billions of years ago.

Astronomers want to know what will happen to the universe. They think it is still expanding. In fact, the universe seems to be expanding faster and faster as time goes on. Many astronomers think the universe will go on expanding forever. If it keeps on expanding, everything in the universe will eventually grow cold. Billions of years in the future even the stars will stop shining.

Why is Gold valuable?

“Gold! Gold! Gold!” screamed the newspaper headlines. “Gold discovered in California!” That was in 1848. The news brought 100,000 people rushing to California. They came seeking the yellow metal that could make them rich.

People since ancient times have used gold for jewelry and money. They used it in religious objects and works of art. Wars have been fought over gold. And sometimes, as in California, gold changed the course of history.

Gold is unusual among metals. It does not rust or tarnish (grow dull and discolored). Gold coins recovered from sunken treasures are still as shiny as when they sank.

Gold is soft enough to be easily shaped into jewelry and other items. An ounce (31 grams) of gold can be hammered into a sheet 16 feet (5 meters) on each side. It can be stretched into a wire 62 miles (100 kilometers) long.

People find gold beautiful. And it is rare. All the gold in the world would fit in a cube 65 feet (20 meters) on each side. Because it is so rare, its value doesn’t change much from one year to the next. In ancient times, people could easily carry a lot of wealth in the form of a small bag of gold.


The easiest way to mine gold is with a pan. You fill the pan with sand or gravel that contains tiny bits of gold. Then you swirl the pan under a gentle stream of water. The lighter gravel or sand gradually washes out with the water. The heavier gold particles collect at the bottom of the pan. Gold is so heavy that it doesn’t take many tiny flakes to make an ounce.

Today, gold is most often mined by digging underground with machines. Rock that contains gold is treated with chemicals to separate out the gold. Nuggets of solid gold are quite rare. The largest nugget ever found weighed about 130 pounds (59 kilograms). It was found in Australia in 1869. About two-thirds of all gold mined today comes from South Africa.

Gold is used for many things besides coins, decorations, and jewelry. Gold conducts electricity very well. It is used in tiny electrical circuits. There are very small amounts of gold in your computer.

Gold is also used to protect tall buildings and spaceships from the Sun’s heat. The Sun's rays bounce off even a thin coating of gold. Gold-coated mirrors are used in telescopes. Dentists use gold for tooth fillings. Gold is even used in medicine, to treat cancer and arthritis.

Gold has always made people who controlled it wealthy. Folktales of many peoples tell of greed for gold. The ancient tale of King Midas tells of a greedy king. Midas wished that everything he touched would turn to gold. But he was sorry when his wish was granted. He could not eat because his food and water also turned to gold.

In the 1500s, the Spanish conquered Mexico and Peru while searching for gold. They brought back tons of gold looted from native peoples. The peoples of those regions had never considered gold very valuable.

The discovery of gold in parts of western America and Australia brought in thousands of people seeking quick fortunes. Many stayed on and settled those regions.

How do Crystal form?

Look closely at some table salt through a magnifying glass. You’ll see that the bits of salt are made up of tiny cubes. Each cube is a salt crystal. The salt crystals within the particles can be different sizes, but they always have this shape.

A crystal contains identical particles that are arranged in a particular pattern such as a cube, rectangle, or hexagon. As a crystal grows in size, this pattern is repeated over and over.

Salt is made up of the elements sodium and chlorine. Extremely tiny particles of sodium and chlorine, called atoms, form a repeating cubic pattern in a crystal of table salt. The more times the pattern is repeated, the bigger the crystal that forms.

Crystals form when some liquids turn into solids. A liquid may freeze into a crystal. Snow, for example, is made of tiny crystals of frozen water. Crystals can also be left behind when a liquid dries out. When seawater in a rock pool dries out, tiny crystals of salt remain.

Most of the rocks and minerals in Earth’s crust are crystals. Some crystals were formed from melted rock when it cooled and became solid. Others were left behind by the waters of a sea, lake, or river that dried up long ago.

Many crystals are beautiful. Diamonds, rubies, and emeralds are crystals that are made into attractive jewelry. Crystals also have many practical uses. Quartz crystals are used in clocks, radios, and sonar, the system that allows ships and submarines to see things underwater. Quartz crystals can also be pressed or heated to make electricity.