Phases of the Moon is near the top of the list of concepts that
students seriously misunderstand. Most teachers run into
problems trying to explain the Moon's phases to youngsters. Many
students have trouble imagining how the Moon, half lit by the
light of the Sun, can show phases as a month of time passes.
Visualizing in three dimensions the Earth's unique perspective
relative to the Moon and Sun and visualizing the perspective
from outside the same system of bodies often proves difficult to
students. This demonstration addresses overcoming that
difficulty through the use of two videos clips. The first is a
demonstration of the phases of the Moon as seen from the Earth.
A dark room is required. The video camera represents "Earth," or
someone on Earth looking skyward. For stability the "Moon" is
attached to the Earth using two yardsticks glued together and
painted black. The Moon is a 9" plastic, air-filled ball,
painted with a matt gray spray paint. The "Sun" is a lamp with a
high wattage bulb (e.g., 400 Wat