Describes the forty-year effort of John Harrison to invent the chronometer, the first instrument able to keep accurate time for navigational purposes. "Anyone alive in the eighteenth century would have known that "the longitude problem" was the thorniest scientific dilemma of the day -- and had been for centuries. Lacking the ability to measure their longitude, sailors throughout the great ages of exploration had been literally lost at sea as soon...

Polly's got a pen pal - in Canada! Polly's sure that she and her new friend, Ally, will have a lot in common. When Ally writes that she's 125 centimeters tall and weighs 25 kilograms, Polly wants to know if she's the same. Polly wishes she could go and visit her -- but Ally lives 450 kilometers away! Young readers will learn about metric units like centimeters, kilograms, kilometers, and liters as they follow this story of two friends who can't be...

Join the LeapFrog friends as they discover that fun, learning-filled adventure comes in all shapes and sizes. There's a new machine at the Letter Factory, but no one knows what it's supposed to do. With only a map and a few clues, Leap, Lily, and Tad set out to unlock the machine's secret, embarking on an amazing journey that will teach them about shapes, fractions, and measurement, and give them the tools they need to solve the Great Shape Mystery....

Jenny and Jeff are driving their little sister nuts with their contest fighting over who is best, and now that they are moving into a new house, they are arguing over whose room is bigger, so the children work together to calculate area to settle the debate.

Measurement is a fundamental concept that underpins almost every aspect of the modern world. It is central to the sciences, social sciences, medicine, and economics, but it affects everyday life. We measure everything - from the distance of far-off galaxies to the temperature of the air, levels of risk, political majorities, taxes, blood pressure, IQ, and weight. The history of measurement goes back to the ancient world, and its story has been one...

Marvelosissimo the Magician explains the development of standard units of measure, and shows the simplicity of calculating length, height, weight, and volume using the metric system.

The ants need to plan the Blowout Bug Jamboree! But how can they build a thrilling carnival ride for the festival if they don't know how many bugs will come, or how big those bugs will be? This is a colorful and fun-filled introduction to nonstandard measurement, comparison, and organizing and representing data. As caterpillars, butterflies, and other insects are measured and compared in lengths of ants, an amazing plan unfolds. Just in time for the...