Understanding Seasons - A Model
From the University of Wisconsin SpacePlace
- Seasons are not caused by the Earth being sometimes closer to and sometimes farther away from the Sun.
- Seasons are caused by the tilt of the Earth's axis. When the Northern Hemisphere tips toward the Sun, we have
summer and the Southern Hemisphere has winter.
- It is colder in the winter because the days are shorter, nights are longer, and the Sun is lower in the sky.
- It is hotter in the summer because the days are longer, nights are shorter, and the Sun is higher in the sky.
- At the equinoxes day and night are equal in length.
- You can build a model of the sun and Earth to help students understand the effect of the tilt of the earth
on the seasons.
- 1 Styrofoam ball
- 1 large paper clip
- 2 paper fasteners
- Crayons or markers
- 2 tagboard circles (one slightly larger than the other) You can use 2 different sizes of paper plates.
- Cut out the smaller of the two circles. In the middle of the circle draw the sun.
- Draw the dividing lines on the circle. You will need four parts.
- Label them going counter clockwise around the circle - Winter Solstice, Vernal Equinox, Summer Solstice, and
- Decorate each quarter with things that you enjoy doing during each season.
- Cut out the large circle.
- Using one of the paper fasteners, connect the two circles. Try to put the fastener as close to the middle of
the two circles as possible.
- Take the paper clip and bend the outside prong towards you about 23 degrees. Bend the inside prong in, closing
the end to make a circle. Insert the paper fastener in the circle and place the paper clip contraption to the edge
of the larger circle.
- Draw a circle around the Styrofoam ball to represent the equator and attach the ball to the end of the paper
clip was bent (23 degrees).
- Now, being careful to always keep the Earth (Styrofoam ball) lifted in the same direction, move the larger
circle around and see how our seasons occur.
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