Time Zones

Gr 3—5—Adler offers a simple but thorough explanation of time zones and why people experience different parts of the day simultaneously depending on their location around the globe. Illustrations of an astronaut and his robot dog provide a perspective from high above Earth, which helps readers visualize the way sunlight reaches different parts of the planet as it rotates. The author explains how the need to set railroad schedules led to setting standard times in the United States and Canada in 1883. A year later 20 countries agreed to divide the world into 24 time zones, establishing Greenwich Mean Time as the starting point. Numerous maps and diagrams help visualize these abstract boundaries, including the international date line in the Pacific. The illustrator even introduces some Martian observers who want to learn about the subject. Adler explains the impact of daylight savings time and includes a simple experiment for readers to see for themselves how noon and midnight occur simultaneously on opposite sides of the globe. The clear visual and verbal presentation of this basic topic makes the book a worthwhile purchase for most libraries.—Kathy Piehl, Minnesota State University, Mankato