A simple explanation of how the rotation of the earth causes night and day.

Explains the processes by which a hamburger and other foods are used to make energy, strong bones, and solid muscles as they pass through the digestive system.

Introduces the way in which the sun's relationship to the earth is responsible for seasonal changes.

Explains how bacteria and viruses affect the human body and how the body fights them.

Explains the phases of the moon--the changes that seem to happen to it as it goes around Earth.

An introduction to the human skeletal system, explaining how the 206 bones of the skeleton join together, how they grow, how they help make blood, what happens when they break, and how they mend.

Read and find out about one of nature's most mysterious forces-the earthquake. Some earthquakes are so small that you don't even feel them, while others can make even big buildings shake! Learn why earthquakes happen, where they are most likely to occur, and what to do if one happens near you.

Explains the basic characteristics of weather--temperature, humidity, wind speed and direction, air pressure--and how meteorologists gather data for their forecasts.

Even though Mount Everest measures 29,028 feet high, it may be growing about two inches a year. A mountain might be thousands of feet high, but it can still grow taller or shorter each year. Mountains are created when the huge plates that make up the earth's outer shell very slowly pull and push against one another. Read and find out about all the different kinds of mountains. The earth's continents rest on plates that move slowly across our planet's...

"Explores the mysteries of bird migration, including theories on how birds find their way and how scientists learn about migration"--Title page verso.