axles

An introduction to wheels and axles, explaining what they are, and looking at examples of how they are used.

An introduction to wheels and axles that describes their parts, functions, uses, and history.

Explains the concepts of work and friction; describes machines, wheels, and axles; and includes simple experiments.

Text and illustrations describe the simple machines of wheels and axles.

Photographs and simple text describe how wheels and axles work in simple machines.

Introduces young readers to wheels and axles, explaining what they are, how they work, what they have been used for throughout history, and how they might be used in the future.

Introduces the wheel and axle as a simple machine that can make it easier to move heavy objects, as well as to flatten dough.

An exploration of wheels and axles that defines what they are; discusses their parts, how they work, their history, and how they are used; and includes a related experiment.

A photographic introduction towheels and axles for beginning readers, explaining what they are and how they work, looking at examples of wheels and axles, and discussing their use in complex machines.

Introduces the science of how wheels and axles work and describes different kinds of wheels and the use of wheels throughout history.