DIY Homeschooler

Here is a free find from the BBC to help avoid summer brain drain: A History of Navigation. This now archived interactive explains the era of exploration in the 15th and 16th centuries.

Exploring new territories required accurate navigation, which led to a fierce competition between Britain, France, Holland, and Portugal. The goal: measuring longitude at sea.

Which brings us to the question: How did early explorers, such as the Vikings, navigate?

This interactive walks us through an introduction to navigation including the importance of longitude.

To measure longitude (where you are on the east-west axis of the world) you need to know the time difference between where you are standing, and some other known fixed point.

In an hour, the Earth rotates through 15 degrees (equal to 360 degrees every 24 hours). Thus, if you know that the time difference between you and a fixed point is five hours you know you are 75 degrees east or west of that point, and can show this on a chart.

Various instruments are explained, along with the importance of Cook’s voyages and the development of Greenwich Mean Time (GMT).

This is a great interactive for summer. One way to Keep ’em Learning!

Free Resource

• A History of Navigation
• A History of Navigation (archived — helpful if you don’t have flash installed)

Suggestions

• Explain how early explorers calculated latitude (sun, moon, and stars).
• Why was calculating longitude more difficult?
• Why were the explorations of Cook so important? (maps and charts)
• View Ptolemy’s Cosmographia.
• Name several of the instruments used prior to Cook’s voyages.
• Why is accuracy so important when dealing with longitude?
• Explain Greenwich Mean Time (GMT).
• Where are you relative to GMT?

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Additional Resources

Map and Compass Activities ~ Free
Summer is a great time to get outside and practice orienteering skills!

Cardinal Directions Resources & Mapmaker Kit {Free}
Begin at the beginning with younger students with these six engaging activities.

Maps: A Unit Study
Gerardus Mercator was born on March 5, 1512. Map unit resources.

Longitude by Dava Sobel
Fascinating for older students!