Finding Longitude

The rotation of the Earth means that unless you know the time at 0º longitude you cannot work out your own longitude. At sea, with no sight of land, this means that you do not know your east or west position. Back in the eighteenth century, not knowing longitude at sea cost many lives and eventually something had to be done. In 1714 Parliament decided to do something quite remarkable. It offered a prize, worth around £2 million today, for any solution, provided that it could be tested on real sea voyages across the Atlantic Ocean.

This is a short account of the problem and how it was solved. There are questions to help define the problem and answer pages to help you.Wikipedia covers this story very well. For a fascinating broader view see the book below, by Richard Dunn and Rebekah Higgitt, which can be found online.
The time pieces and other artifacts are on display at the National Maritime Museum in Greenwich.

This resource is suitable for ages 11-14 as a starter or follow up resource.


1. Longitude. The problem

2. Longitude. The prize

3. Longitude. The Winner

ISBN-0-00-794052-3 first published 2014

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© National Maritime Museum, Greenwich, London