The world is filled with machines that make our lives easier. Many of these machines are run by electricity, but you also can use your own power to run machines as well. You power your bicycle you open a door you move a box. Simple machines are devices with very few parts that help us move objects. Learn about the basic simple machines that we use every day.

Discover what Earth looks like from space, how the Earth moves through the solar system, what the conditions are for life on Earth, what you would find if you dug a really deep hole, what it is like on the Moon, and what space missions have taught us about Earth. Features time lines, drawings, photos, and an easy-to-understand explanation of global warming.

How scientists find out how things work: First a scientist pulls together all the observations about something. Next, he or she thinks up a question that the observations don't explain. Then a hypothesis, that which someone believes to be the correct answer to the question is formed. It must be a statement that can be tested. Next, an experiment is made to test the hypothesis in which everything that happens is written down. Finally the scientist...

Provides information about Mesopotamia, discussing the importance of two rivers to the civilization, city-states, empires, ziggurats, reading, writing, and other related topics.

"This book details the science of electricity and magnetism. It explains how these forces work, how they are related, what uses people have found for them, and more."--

Whether youre walking along a busy city street or enjoying the solitude of the wilderness, you are always surrounded by sound. Readers will learn how sound waves are formed and how they change as they move. They will also find out how people hear sound, how sound waves can be used in unexpected ways, how the properties of a sound wave affect the way it is heard, and much more.

"This book details the history, current uses, and potential future applications of solar energy."--

"Learn all about Hawai'i Volcanoes National Park, including how it was formed, which wildlife can be found there today, and how it is affected by environmental issues."--Provided by publisher.

"Where did British colonists first settle when they came to America? Jamestown, Virginia became the first British colony in America when it was settled in 1607. Inside [this book] you'll find: Which Native American groups lived in Virginia; a timeline, photos -- and what Virginians do for fun; surprising true facts that wills shock and amaze you!" -- Back cover.