Walker, Sally M

Explains the concept of work, describes machines and different types of screws and how they are used, and includes simple experiments.

Explains the concepts of work, gravity, and friction, describes machines and different kinds of pulleys, and includes simple experiments.

Tells the story of Dr. William Hammer and his crew, who, in 1991, discovered dinosaur bones in Antarctica.

An introduction to fossils, our window into the past.

Describes the types of sedimentary rocks, and the processes that lead to their formation.

Describes minerals, what they are made of, identification of minerals, and uses for minerals including salt for flavor, diamonds for beauty, and more.

Describes the Earth's different kinds of rocks and how they were formed.

Describes the life and accomplishments of baseball star Jackie Robinson, who became the first African American in twentieth-century major-league baseball.

Eight-year-old Letty attempts to save her pet goose from marauding British soldiers in New Jersey during the Revolutionary War.

Describes volcanoes, where they form, the kinds of lava and landforms they create, and how volcanologists are learning to predict eruptions.