Describes the concept of time and how it has been measured throughout history, using water clocks, sundials, calendars, and atomic vibrations.

"The mathematical concepts of elapsed time, converting units of time, and equivalent units of time are introduced as readers learn about astronauts aboard the International Space Station. Concepts include adding and subtracting units of time, using a number line diagram, and time intervals. This book features a discover activity, connections to science and history, and mathematical vocabulary introduction"--

Simple text introduces the concept of time and how time is measured using the sun, calendars, clocks, watches, and timers.

"Simple text and photos explain a day as a unit of time and the parts of a day"--

"Real-world examples and engaging activities guide readers in learning about measuring time from an analog and digital clock using a.m. and p.m. Readers practice selecting appropriate measuring tools and units of measurement, converting between units, and solving problems by measuring"--Provided by publisher.

Readers learn what the clock measures and why knowing how to tell time--in seconds, minutes, and hours--is important. They learn the history of the clocks, including sundials and hourglasses. They also learn how to read analog and digital clocks to tell time. Sidebars instruct math by showing readers how to add and subtract hours.

Describes the concept of time and the different ways it can be measured.

"Simple rhyming text and color photographs present seconds as a unit of time"--

Learn about different ways to measure time by following the growth of a baby chimp Late one night, a tiny chimpanzee is born at a zoo in Kansas. He seems very weak, and the staff is worried. Will he survive? When the mother shows no interest in her baby, a pediatrician comes in to care for the little chimp. The baby grows strong and healthy, and soon he is big enough to be moved to the Denver Zoo. He is named Jiggs after the doctor who saved him. Jiggs...