This lesson will require one 30-minute period. 301-20: observe
and explain how the relative positions of Earth, the Moon, and
the Sun are responsible for the moon phases, eclipses, and
tides. Students in this lesson will be introduced to the concept
of tides and tidal forces, and will be asked to discuss the
benefits of tides to life on Earth. Nota : This page contains
documents for which the access may require a particular
software. If the software is not installed, you can download it
and follow the instructions for installation. Open class by
asking students to hypothesize as to the cause of the tides;
have them discuss how they believe the Moon to be the cause, and
ask if the Sun is involved in any way. Introduce the Tides
applet. Explain the forces at work: For the millions of people
in the world living along the ocean, the daily fluctuations of
the water level are an important fact of life. Tides occur
because of the gravitational attraction between the water in the
oceans and the Sun and Moon. The Sun