Solar and lunar eclipses are some of the most spectacular phenomena that occur in our skies. For millennia, people have looked to these events as a way to predict the future, as actions of the gods, and, rarely, as what they actually are: the earth, moon and sun lining up. Because these astronomical bodies travel on plotted paths, when and where they will occur is predictable -- making a perfect subject for a classroom unit in the days leading up to or following a lunar eclipse, or more rarely, a solar eclipse.
- Skill level:
- Moderately Easy
Other People Are Reading
Things you need
- Aluminium foil
- Lamp or flashlight
- Sunglasses (optional)
Cut the cardboard into a large circle, at least a foot in diameter. If using a lamp, a circle of at least two feet in diameter is preferable.
Cover the cardboard circle with aluminium foil. Only one side is necessary, though the foil holds better if wrapped all the way around. This will be the moon.
Place the lamp near the edge of a desk or table easily visible to all the kids. This will be the sun. If using a flashlight, have a student volunteer to hold it facing forward at about shoulder level.
Have a student volunteer to be the earth. If using sunglasses, have this student put them on.
Setting Up the Solar System
Have "Earth" stand a few feet away from the "Sun" and hold the "Moon" out at arm's length, with the foil-covered side facing her.
Have Earth spin slowly in a circle a few times, to give the students an idea of the moon's usual orbit around the earth.
Have Earth stop with the Moon directly between herself and the Sun. If necessary, adjust the student's arms and stance so that the light source, the student's eyes, and the Moon are in alignment.
Ask Earth if she can see the Sun -- the answer should be no. Explain to the students that this represents a solar eclipse, with light from the sun that normally reaches earth being blocked by the moon.
Performing a Solar Eclipse
Choose a new student volunteer or volunteers, if desired. Now have Earth spin around in a few slow circles, and ask him to notice how the Moon reflects light from the Sun.
Explain that this reflected light is the source of all moonlight -- the moon makes no light of its own.
Have Earth stand with his or her back to the Sun, still holding the moon out at arm's length. Make sure that the student is blocking the light from the Sun.
Ask the student whether there is still any "moonlight" reflecting back -- the answer should be no. Explain that this is what happens when there is a lunar eclipse: the earth comes between the sun and the moon, and thus no light from the sun reaches the moon. Because the moon only shines as a result of this reflected light, the moon turns dark, or is eclipsed.
Performing a Lunar Eclipse
Tips and warnings
- If any student notices that the moon would eclipse every time it goes behind the earth, and the sun would eclipse every time there's a new moon, explain that the moon's path is not actually in the same plane as the earth's path around the sun. Most of the time the moon is too high or too low, and thus the earth does not block the path of the sun's rays. This can be demonstrated by having "Earth" hold the moon up above his or her head.
- The EarthSky page listed under references has a nice animation showing this path, though the narration might be too sophisticated for younger students. With the youngest students, it is likely best to avoid this topic if possible. Older students can be directed to perform an orbit that already takes this into effect during the initial spins, pre-empting the question.
- 20 of the funniest online reviews ever
- 14 Biggest lies people tell in online dating sites
- Hilarious things Google thinks you're trying to search for