Explains what comets are, how they are formed, and how their unusual orbits bring them into earth's view at predictable intervals, with a special focus on Halley's comet.

Describes the origin and nature of tornadoes and how to stay safe when threatened by one of these dangerous storms.

Describes how magnets work and includes instructions for making a magnet and a compass.

A simple explanation of the water cycle, clouds, water vapor, condensation, evaporation, rain, and hail.

Introduces the solar system and its nine planets. Includes directions for making two models, one showing relative sizes of the planets and the other their relative distances from the sun.

Explains how volcanoes are formed and how they affect the earth when they erupt.

Explains in simple text and illustrations what is known about the force of gravity.

Explains how volcanoes are formed and how they affect the earth when they erupt.