America’s founders did debate a bit as to whether or not to force children to attend schools, and they decided to leave such decisions to individual families and local and state governments. The words “education” and “school” do not appear in any of our founding documents, such as the Declaration of Independence, the Constitution, or the Bill of Rights.
Some of our most famous inventors, writers, and politicians were self-taught, learning through mentoring or apprenticeships, conversation, and reading. In 1850, Massachusetts became the first state to institute a compulsory schooling law.
When you flush the toilet or wash your clothes, the used water, called wastewater, goes down the drain. This wastewater travels through a network of underground pipes known as the sewer system. The city system treats the wastewater to keep it clean. Both large objects, such as sticks, cans, rocks, and small debris, such as gravel and sand, are separated from the wastewater.
It is treated with oxygen, which allows micro-organisms to grow and eat small bits of organics. The wastewater is then recycled and clarified again. The wastewater is then disinfected with chlorine to kill harmful pathogens before being released into a nearby river, lake, or sea. In towns that do not have a sewer system, each house has its own septic system. Toilet water flows into a big underground tank where bacteria helps break down the waste. Then the water flows out into the soil, where it is absorbed.
According to a national survey conducted by the American Pet Products Manufaturers Association in 2008, Americans owned about 75 million dogs and 88 million cats. Approximately 39 percent of U.S. households own at least one dog, and 34 percent own at least one cat.
According to the American Kennel Club, Labrador retrievers are the most popular dog breed, followed by Yorkshire terriers, German shepherds, and golden retrievers. Persian cats are the most popular feline breed, followed by the Maine coon and the Siamese. Combined reptiles are the next popular type of pet, followed by birds and horses.
Yes. Even though it may feel awkward or embarrassing, it helps to tell your parents, a teacher, or a counselor about a bullying experience. A trusted adult can make you feel better by explaining why bullies behave the way they do and by reassuring you that what a bully says about you has nothing to do with who you really are.
Adults can help keep you safe if you’re being threatened, and come up with solutions to deal with the bullying. Many states have bullying laws and policies, and many schools have programs in place that educate parents and kids about bullying.
Living creatures need oxygen to survive, and fish are no exception. Human beings 68 use their lungs to take in oxygen, and fish breathe using their gills. A fish’s gills are full of blood vessels that absorb the tiny particles of oxygen from the water.
The fish sucks the water in through its mouth and squirts it out through its gills; during this process, the gills take the oxygen from the water into the blood vessels. A fish’s gills are not constructed to take oxygen from the air, so they cannot breathe on dry land.
Eyelashes protect our eyes. They help keep small particles and dust out of our eyes, especially when the wind is blowing. Eyelashes are also super-sensitive, and they alert the eyelids to shut when something touches them. If you rub your finger against your eyelashes, you will find that your eyelid automatically shuts.
But be careful not to rub too hard—if you lose a lash it will take about four to eight weeks to grow back! Fortunately, your upper eyelid has between 100 and 150 lashes.
Carved into the southeast face of a mountain in South Dakota are the faces of four presidents: George Washington, Thomas Jefferson, Theodore Roosevelt, and Abraham Lincoln. Known as Mount Rushmore, these 68-feet (20.7 meters) high granite sculptures were the brainchild of South Dakota state historian Doane Robinson. In 1923, he conceived the project to attract more people to the Black Hills of South Dakota.
Congress passed legislation that authorized the carving in what is today known as Black Hills National Forest. In 1927, the sculptor Gutzon Borglum and 400 workers began the project, using dynamite to remove unwanted rock. Mount Rushmore was completed in 1941.
Rain forests—thick forests of trees and other plants found in the lowland areas of the Tropics around the world—exist in parts of Australia, Indochina, India, the Malay Peninsula, the East Indies, in central and western Africa, and in Central and South America. Unlike forests in many other parts of the world, which have been affected by global climate changes like the Ice Age, tropical rain forests have been growing uninterrupted in some places for millions of years. During that time an unimaginable number of different types of plants and animals have evolved to use every food source and live in every spot there. Tropical rain forests have more plant and animal species than the rest of the world combined, and scientists continue to discover new species. Because tropical rain forests are located near the equator, their climate is warm.
The name “rain forest” comes from the fact that they receive a lot of rain—between 160 and 400 inches (4 and 10 meters)—throughout the year. Plants grow very quickly under such ideal conditions. In order to get the sunlight that they need for photosynthesis (the process by which they and other green plants make their own food), rain forest trees grow very tall, up to 130 feet (40 meters) high. Their tops form a huge canopy that shades most of the ground, protecting plants on the ground from excessive sunshine as well as wind. Rain forest trees have very shallow roots, for the soil in which they grow is poor, having long been depleted of nutrients by the needs of thick plant life over millions of years. But the abundant life all around contributes organic matter (the decomposed remains of plants and animals) to the surface of the soil, which is enough to nourish these grand, ancient forests.
In many cultures shaving is forbidden. The reason we in the West lather up every morning can be traced directly back to Alexander the Great. Before he seized power, all European men grew beards.
But because young Alexander wasn’t able to muster much facial hair, he scraped off his peach fuzz every day with a dagger. Not wanting to offend the great warrior, those close to him did likewise, and soon shaving became the custom.
Skin color—which ranges from light pink to dark brown—is determined by the amount and type of the pigment melanin there is in the skin. Melanin comes in two types: phaeomelanin (red to yellow) and eumelanin (dark brown to black).
Both amount and type are determined by four to six genes. One copy of each of those genes is inherited from your father and one from your mother. Each gene comes in several coding sequences, which results in a variety of skin colors around the world.