In the mid-1900s, a biologist named Rachel Carson was afraid that some day there might be no more birds. Farmers were spraying a chemical called DDT on their fields to kill insects. But DDT was also keeping birds such as the bald eagle and peregrine falcon from having babies. DDT prevented the babies from hatching. She wrote a book called Silent Spring to warn about the dangers of DDT.
Pollution happens when chemicals that are harmful to living things get into the environment. Rachel Carson feared that DDT would get into the food people ate. Her book scared a lot of people. Governments banned the use of DDT. People then began to worry about other kinds of pollution. They worried that pollution could harm people’s health.
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.
Can you imagine growing taller than a ten-story building? How about living to be 4,000 years old? Ever grow 2 inches (5 centimeters) in one day? Such things are not likely to happen in your life. But life would be very different if you were a tree!
WHAT IS A TREE?
Trees are plants. They are usually tall and have a main stem called a trunk. They come in many colors and sizes. The tallest trees are the tallest plants on Earth. Some trees can grow as tall as a soccer field is long. Trees grow everywhere on Earth, except for deserts at the equator and the North and South poles.
Think of all the things you throw away: juice bottles, soda cans, candy wrappers. It adds up. How much trash do you produce?
Americans throw away an average of 1 ton of trash per person every year. That’s 2,000 pounds (907 kilograms) of garbage! Most of this trash gets buried in big holes in the ground called landfills.
A lot of this garbage can be recycled, or turned back into something useful. Just about any material can be recycled. The main things we recycle today are made from metal, paper, glass, or plastic.
Have you ever played the cloud game? You lie on the grass and look up at the clouds. You try to see different shapes in the clouds. One cloud might look like the head of a horse. Another might look like a car. You watch as the clouds move across the sky. You watch the clouds change shape as they move.
WHAT ARE CLOUDS MADE OF?
Clouds are made of small drops of water or tiny pieces of ice. The water and ice in clouds come from Earth’s surface, especially from lakes, rivers, and oceans. Water on the surface evaporates. It changes into a gas called water vapor. Water vapor goes up into the air.