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Solar Eclipse

 

Overview

Eclipses have frightened, mystified and puzzled man since antiquity. The Chinese believed that an eclipse was caused by the celestial dragon eating the Sun. Tablets found in northwestern Mexico show that the Mayan Indians began making eclipse predictions and keeping records 2000 year ago. Even today, people travel great distances to witness this celestial alignment that brings awe and wonderment to all who see it. A solar eclipseoccurs on Earth when the Moon blocks the Suns light due to the relative positions of the Earth, Moon and Sun. The Sun is 400 times larger than the Moon and the Moon is 400 times closer to the Earth than the Sun. The Sun and the Moon cover approximately the same area of the sky so that they appear to be the same size in the sky. During a new Moon phase, the Moon is positioned between the Sun and the Earth. However, not every new Moon produces a solar eclipse, because the orbit of the Moon is slightly tilted with respect to the orbit of the Earth around the Sun. Only when the Moons orbit brings it into direct alignment between the Sun and the Earth will the Moons shadow fall on the Earth. The shadow is called the umbra, and during a solar eclipse sweeps darkness in a band 300 kilometers wide across the Earth at 1700 kilometers per hour! People inside the umbra will see the Sun completely blocked by the Moon. People outside this path, in an area known as the penumbra, will see a partial eclipse, where the Moon only hides a portion of the Sun.

Activity

Because of the intensity of the Sun’s light, it isn’t safe to look directly at the Sun during an eclipse. That’s why you’ll need to build a projection camera to protect your eyes. Once you’ve built the camera in this activity, you will be able to observe the contacts of an eclipse. Materials:
  • Two, five-gallon ice cream containers
  • Aluminum foil
  • White paper
  • Tape
  • Pin
  1. Cut a three cm hole in one end of the ice cream container.

Resources

  • Aveni, Anthony. Skywatchers of Ancient Mexico. University of Texas Press, Dallas, 1980.
  • Dyer, A. ?When Worlds Align.? Astronomy, Vol. 19, No. 7, pp. 62-73, July 1991.
  • Gingerich, O. ?The Making of a Prize Eclipse.? Sky & Telescope, July 1991, pp. 15-17.
  • Littmann, Mark and Wilcox, Ken. Totality: Eclipses of the Sun. University Press, 1991.