Ancient Mathematics and Science: The Circle and Navigating by the Stars

"Oak and triple bronze must have girded the breast of him
who first committed his frail bark to the angry sea."
--Horace, Odes

In this ancient Babylonian map, the world is a circle with Babylon at its center. Ancient Babylonians were the first to divide the circle into 360 degrees (how we also got our 60 min / 60 sec clocks), and they may have been among the first to use the wheel.

As it turns out circular divisions were an important tool for sea explorations, and they were essential for the growth of many ancient civilizations. Read the student links at this Navigating by the North Star lesson plan. Because of its location, the North Star is a reliable landmark that can be used for determining one's location on the earth.

The bottom figure at left shows a photograph taken with the shutter left open. The "star swirl" occurs because the other constellations rotate around the fixed position of the North Star over the course of the evening.

Read about How a Sextant Works and build one here.

Would you know how to use it to determine your latitude? If you have an accurate clock set to Greenwich Mean Time, you can also calculate your longitude.

If you have Shockwave, you can play this game Escape from Antartica and see if you can find your way home like Ernest Shackleton.

Classical Science: Telling Time with the Sun

Time to run outside in the sun!

For a simple animation of how shadows vary with time and position of the sun, click here. The animation here shows you how to estimate the size of a very large object (like the Statue of Liberty or T Rex) by comparing shadows.

When Isaac Newton was a boy, he was interested in studying the patterns of how shadows moved. He eventually constructed many sundials around his house and could tell the time just by looking at the placement of shadows.

For a good background on telling the time by the sun, and a print-out template for one to make yourself, click on this NASA site. You'll have to determine your latitude before you can use the sundial accurately so that you can factor in the tilt of the earth and its curvature. There are many beautiful sundial pictures at Wikipedia.

Another device an ancient Roman could use was an horologium ex aqua, or water clock - that displayed the month and hour on a column of water. For more on how ancient Romans kept time, check here.

If you're wondering how a person in the Middle Ages might have been able to tell the time at night, they could have used a Star Clock that uses the pointers of the Big Dipper.

Technorati tags: classical education, science, astronomy, sundials

Spring Equinox Tomorrow - March 20, 2007

Tomorrow is the Vernal Equinox, or "Equal Night" - or what many note as the first day of Spring. The days will start to get longer after this, and the nights shorter. Because the sun will pass directly over the equator, days and nights will be of equal length all over the world during equinoxes. The official date of Easter is designated as the first Sunday after the first full moon after the vernal equinox.

Spring Equinox
Introduction to Astronomy - Vernal Equinox