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From a distance of 10 feet, shine a slide projector on a
globe of the earth. Hang a styrofoam ball from a string,
and slowly move it counterclockwise around the globe.

You will see that when the ball, which represents the moon,
is between the globe and the light source, a shadow is cast
on the globe. Compare this to an eclipse of the sun.

When the sun, moon, and earth are in such positions, a solar eclipse occurs. Now continue the revolution of the ball until it is behind the globe. Make an analogy to an eclipse of the moon or a lunar eclipse.

Try moving the three objects to find a way to explain why
eclipses are not observed at each new moon and full moon.
(Only a moon orbit tilted relative to the earth's orbit around the sun will produce infrequent solar and lunar eclipses.)

A month or two in advance of a solar eclipse, draw a picture of the eastern horizon early in the morning (moonrise and sunrise). Every week on the same day, mark the location of the moon and sun on the picture.

You will see that as the week of the eclipse approaches, the setting points get closer and closer together (they will eventually coincide exactly if there is a total eclipse).

If the plotting is continued for several weeks after the eclipse, observing the evening western horizon (sunset and moonset), you will see the two paths separate.

This note of caution is repeated, for safety's sake, in other projects:

Caution: No direct observation technique for viewing the
sun is safe. Looking through exposed photographic film, sun glasses, smoked glass, or similar materials is also unsafe. The only advised technique is to view the sun indirectly using a pinhole device.

I think the intense light of the sun (and probably other lights, too, such as lasers) burn the retina of your eyes.

The brilliant scientist says: "Direct viewing of the sun, even for a short time, can cause burns to the eye's retina. Burns will not be felt but can produce a permanent blank spot in the field of vision."


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