George Washington helped form the United States into what it is today by making wise decisions. After becoming a war hero in the French and Indian War, he went on to lead a fight against the British in the American Revolution. He continued his legacy by becoming the first president of the United States.
Take a trip to the world market for an exciting way to learn about standard measurement! This title takes young readers to markets around the world, showing them how to measure common food items with standard measurements. Some things are measured by length! Some things are measured by weight! Children will learn these and other measurement techniques through vibrant images, fun examples, and simple mathematical charts, enhancing their mathematical and STEM skills.
John Jay served in all three branches of the government. Once the Constitution was written, he was a staunch supporter of the document, joining some other men in anonymously writing â€œThe Federalist Papers,â€ which explained to the public why the Constitution should be ratified. Soon after, he was made chief justice of the Supreme Court, and he was given the position of declaring laws unconstitutional for the very first time.
Lewis and Clark were commissioned by President Thomas Jefferson to find a water route from the Mississippi River to the Pacific Ocean. The men were also asked to explore the newly purchased Louisiana Territory. They never found a water route, but they successfully documented information about the new lands.
James Madison made great contributions to the United States. During his presidency, he declared war on Great Britain. Not all of his decisions met public approval, but he was well respected throughout his lifetime and one of the most influential founding fathers.
Laura Ingalls Wilder grew up as a pioneer girl and endured the difficult times in the West. Wilder made important contributions to the West. Other pioneer women contributed as well, including Narcissa Whitman, the first female pioneer.
Harriet Tubman was a slave who dreamed of freedom from a very young age. After her escape at 29, she did everything she could to help and rescue other slaves. In her later years, she built a home to take care of elderly African Americans with no place to live and encouraged women to stand together for their rights.
Sitting Bull was a powerful Hunkpapa Lakota Indian Chief whoâ€”along with the Lakota Indians and other nearby tribesâ€”was involved in brutal battles with the United States over land issues. All tribes that were fighting to avoid the reservation eventually surrendered, and the Lakota people were no exception.
Abraham Lincoln was president during one of the most unique times in history. With a country on the brink of war, his ultimate goal was to keep the Union together. When Lincoln freed the slaves, he angered many Southerners, including his assassin, John Wilkes Booth.
Ulysses S. Grant was a warrior, hero, and a compassionate soldier. Grant led the Union army to victory during the Civil War. The North thought of him as a hero for ending the Civil War and elected him president of the United States.
Some of the first geologists came from ancient Greece and Egypt. Later, scientists in China studied how land was formed and figured out how erosion wears away mountains, rocks, and other landforms. Scottish scientist James Hutton's The Theory of the Earth became the basis for modern geology. William Smith started out as a farmer, but went on to create what is thought to be the first geologic map. German Friedrick Mohs studied minerals and came up with a hardness identification scale that is still used by every geologist.
Maps and globes are among the most important tools that scientists have for studying the earth. In the 1500s, Gerardus Mercator created the first globes and maps. William Davis helped make geography a school subject and is a founder of geomorphology, the study of landforms. He also made important discoveries about the cycle of erosion. Many of today's discoveries come from photos taken from satellites that orbit our planet.
Alfred Wegener studied astronomy and meteorologyâ€”and was even a record-holding balloonistâ€”before he became famous for his theories on how the land and seas on Earth were formed and change. These ideas are continental drift and plate tectonics. Seeing that the continents fit together like a puzzle, Wegener proved the theory that all of Earth's continents were once connected. Although his theories weren't accepted until after his death, scientists use plate tectonics to explain volcanoes and many other changes on Earth.
Ancient astronomers looked at movements in the sun, moon, and stars to guide travelers and keep track of the seasons. Nicholas Copernicus was the first to challenge people's beliefs that Earth was the center of the solar system and is known as the founder of astronomy. Galileo Galilei built a telescope and spotted craters on the moon and sunspots on the sun. Isaac Newton invented the reflecting telescope and discovered the law of gravity. Astronomers continue to work every day to uncover the mysteries of the universe.
Much of what we know today about Earth is from images taken by cameras on powerful telescopes. Edwin Hubble changed our view of the universe. Working in an observatory, he found that there are other galaxies besides the Milky Way. He also showed that the universe is still growing. Lyman Spitzer, Jr. proposed placing telescopes in space, and in 1990, the Hubble Space Telescope was launched. It sends us amazing images of the universe.
Rachel Carson began writing about nature when she was just 10 years old. She became a zoologist in 1932 and went to work for the United States government as a biologist and writer. She wrote about natural resources and encouraged others to care for the planet. She wrote books that helped people understand the world around them. Everyone can play a part in keeping the Earth healthy.
Planck studied physics, the science of matter and energy. He wound up making big discoveries in the area of thermodynamics, which is the study of heat and how it moves. Planck won the Nobel Prize for his work in Quantum Physics, which is the movement inside of atoms. It changed the way scientists understood the world.
Marie Curie's work in radioactivity changed the way scientists think about matter and energy and led to advancements in the treatment of disease. With her fellow scientist and husband, Pierre Curie, she searched for the source of radioactivity and discovered two elements, radium and polonium. They shared the 1903 Nobel Prize, the world's highest science award, for their discovery.
Albert Einstein is probably the most influential scientist and greatest physicist of the twentieth century. He revolutionized our ideas about time and space and is best known for his theory of relativity and his equation E=mc^2, which explains the relationship between energy and mass. By age 30, he was considered by many to be one of the world's greatest scientific thinkers.
Forces can't be seen, but without them, nothing around us would happen! A force is a push or pull that usually causes movement. Friction is a force that opposes motion and slows things down or stops them. Famous scientist and mathematician Sir Isaac Newton wrote the rules about forces and motion.
Isaac Newton is considered one of the greatest scientists who ever lived. His work changed the way humans understand astronomy, physics, math, and more. He is probably most famous for three laws about the way things move, called Newton's Law of Motion.
Electromagnetism is the combined power of electricity and magnetism. Almost everything we doâ€”from watching television to using a computerâ€”is affected by electromagnets. In the 1830s, scientist Michael Faraday proved that electricity and magnetism are different ways to observe a unified force that he called electromagnetism.
There are 90 different elements, like the oxygen that we breathe, that can be found in nature. When two or more elements combine, they are held together by a chemical bond and form a compound. In 1869, chemist Dmitri Mendeléev organized the elements into a chart that is known as the Periodic Table of Elements.
British scientist Robert Hooke built an early microscope and was the first scientist to observe cells and give them their name. Anton van Leeuwenhoek created the best microscopes of his time and used them to study living organisms. Matthias Schleiden, Theodor Schwann, and Rudolf Virchow created Cell Theory, which says that all living things are made of cells; cells are the smallest part of a living thing; and all cells come from other cells.
French scientist Louis Pasteur has been called the founder of modern medicine. He proved that germs spread disease, and his work has saved millions of lives. A university chemistry professor, Pasteur is best known for discovering pasteurization, a process by which bacteria and molds are killed when liquids are heated. The process was named for him and is used today.