The Universe Solar and Lunar Eclipses
Directions: Using a small
styrofoam ball, a pencil, a lamp, and your head, let's try to
understand how eclipses work.
What is a lunar eclipse?
What is a solar eclipse?
We can understand eclipses by creating
models of the Sun, Moon, and Earth.
Place a lamp at the front of the
room and turn it on. (Remove the lampshade, please.)
Stick a pencil into your
styrofoam ball so you can easily hold it.
Turn off the lights.
Stop playing around.
Face the lamp, holding your
pencil/ball at arm's length. The lamp represents our
styrofoam ball the Moon, and your head the Earth.
Move the moon around your head to
model its revolution around the Earth. Position the moon so it's
directly opposite the Sun, with your head casting a shadow on it. When
the Moon passes into the Earth's shadow, we have a lunar eclipse.
What is the area of total lunar eclipse called?
What is the area of partial lunar eclipse called?
Move the Moon around the your head
until it completely blocks your view of the Sun/lamp. When the Moon is
positioned between the Earth and the Sun, a solar eclipse occurs.
Watch the sizes of the shadows. Look at
a friend's face during the solar eclipse. How big is the shadow that
falls on his/her face? _______________
Do more people see a solar or a lunar
Now that you understand what causes an
eclipse, think about lunar phases and how often there should be solar
and lunar eclipses. Experiment with your models. How long it takes for
the Moon to orbit the Earth? _______________ What phase is
the Moon in during a solar eclipse? ___________________ During a lunar
How many times a year do those two
things happen? __________________
If the Moon were orbiting in the exact
plane as the Earth and the Sun, we would have a lunar and a solar
eclipse once a month each. However, the Moon's orbit is tilted to the
plane of the ecliptic. You can demonstrate this by holding a hula-hoop
around the lamp, and a smaller embroidery hoop within the hula-hoop,
tangent to it, and slightly askew to it. The embroidery hoop
represents the Moon's (monthly) path around the Earth, the hula-hoop
the Earth's (yearly) path around the sun. Where do the Moon and Sun
have to be to produce an eclipse?
How many times a year do the Sun and the Moon reach those positions?