Who Wanted to be a Millionaire?
The 1714 Longitude Contest

"During the great ages of exploration, 'the longitude problem' was the gravest of scientific challenges. Lacking the ability to determine their longitude, sailors were literally lost at seas as soon as they lost sight of land. Ships ran aground on rocky shores, those traveling well-known routes were easy prey to pirates.

"In 1714, England's Parliament offered a huge reward to anyone whose method of measuring longitude could be proven successful. (The prize was worth several million dollars in today's currency.) The scientific establishment--from Galileo to Sir Isaac Newton--had mapped the heavens, in its certainty of a celestial answer. In stark contrast, one man dared to imagine a mechanical solution--a clock that would keep precise time at seas, something no clock had been able to do on land. And the race was on...."

Excerpted from the book Longitude: The True Story of a Lone Genius Who Solved the Greatest Scientific Problem of His Time. By Dava Sobel, Penguin Books, 1995.

Learn about John Harrison, an English clockmaker, who solved the Longitude Problem by developing a clock that would keep precise time at sea. With that clock, sailors could know what time it was on board and at home when a single event took place on board (i.e. when the sun reached its highest point in the sky). And by knowing the difference in hours and minutes between the two times, they could then calculate their longitude.

  • Check your library for this book, and consider it for class reading and journaling.
  • Have your students think about the longitude problem of that age. Ask them why was a solution to this problem so critical?
  • Try This! Have students imagine themselves as sailors setting sail on the sea and trying to reach a destination. If they had tools such as maps with latitude and longitude lines, a compass, and the stars and the wind to help them navigate, why were they still be unable to determine longitude?
  • Have your students think about the present day. What do they think is the greatest scientific challenge of today? Why?

For more information about this important scientific discovery, visit these resources:

  • NOVA Online: Longitude and Navigation information including Teacher's Guide, resources, secrets of ancient navigators and more!

  • NOVA video: "Lost at Sea: The Search for Longitude" (call 1-800-255-9424).

National Geography Standards

The World in Spatial Terms

  • How to use maps and other geographic representations, tools, and technologies to acquire, process, and report information.
  • How to analyze the spatial organization of people, places, and environments on Earth's surface.

Human Systems

  • The characteristics, distribution, and migration of human populations on Earth's surface.
  • The patterns and networks of economic interdependence on Earth's surface.

National Math Standards

Numbers & Operations

  • Understand numbers, ways of representing numbers, relationships among numbers, and number systems.
  • Compute fluently and make reasonable estimates.

Problem Solving

  • Build new mathematical knowledge through problem solving.


  • Recognize and apply mathematics in contexts outside of mathematics.

National Science Education Standards

Earth and Space Science

  • Objects in the sky have patterns of movement. The sun, for example, appears to move across the sky in the same way every day. (K-4)
  • Most objects in the solar system are in regular and predictable motion. Those motions explain phenomena such as the day, the year, phases of the moon, and eclipses. (5-8)

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