STC™ Program - Science and Technology Concepts STC BOOKS™ are colorful 64-page readers with research-based science content, giving teachers an ideal way to integrate science instruction during guided, independent, or take-home reading. Teachers use STC™ science curriculum materials to enhance elementary classrooms, increase student test scores, and meet national and state educational standards.

Grades 5-6. Measuring Time covers the history of time measurement and the evolution of timekeeping. Americans use clocks to help structure their lives, but students discover in one reading that accurate clocks are a relatively new invention, coming from sailors' need to know where they were at sea. Looking back in time, the book explains how geologists can tell the age of landforms such as the Grand Canyon, from which can be determined the age of other places as well. Additional stories describe how nature's creatures-including people-regulate their lives though internal "clocks."