Students should now be aware of the great movements
that occur in the Universe. Movement is also present throughout our Solar
System. Even the Sun moves within the Milky Way Galaxy! You may want to ask
them what evidence suggests to us that the Earth moves. The rising and
setting of the Sun and Moon implies that one of the objects is moving. The
changing positions of the stars, Sun, and Moon also implies movement of
The key concepts to emphasize are that the Earth
revolves around the Sun or orbits around a central point. The Earth also
rotates on its axis or on itself. Although simple, these terms are easily
confused. Use the worksheet to help student understand.
An example of revolve and rotation is a person who is
sitting on a horse attached to a Ferris wheel. The person in the horse is
revolving around the center, however rotation of the horse and person would
occur if the person in the horse spins. The Earth, spinning on its axis,
revolves around the Sun. The Moon, rotating on its axis, revolves around the
Rotation is a little more involved because students
need to understand an axis. An axis is an imaginary line around which an
object spins on itself. The Earth's axis is an imaginary line that runs
through the north and south poles. You can use a basketball spinning on a
finger as an example of rotation. Rotation causes day and night, and the
tilt of the axis (23 Ĺ o) causes the seasons. The quality of the sunlight
caused by the tilting of the axis is the major factor causing the seasons,
not the distance from the Sun.
- Ask the students what evidence suggests to us that the Earth moves.
Explain how the passing of day and night are cause by rotation.
- You may want students to work in groups of 4 or 5 and have them
illustrate to you the difference between revolution and rotation.
Students should revolve around a central student, but they should also
be rotating on their axis as they revolve.
- The placemats are a way to get students to learn to observe and
collect information. The orbit of each planet defines their revolution
around the Sun. Point out the rings around Jupiter, Saturn, Uranus, and
Neptune to the students. Tell them that the rings define the planetís
rotation. These objects circle the planet in a band . The planetís
axis is perpendicular to this band.