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The Elementary® planetariums (orreries) are available as lighted models (P-4020-000), or unlighted (P-4010-000) models. These planetariums are suggested for use as a beginning model, and show individual concepts, one at a time. In this model, the Earth and moon are moved separately, by hand. The ladder chain and gear drive is used solely to keep the axis of the Earth pointed at a 23-1/2° angle, toward the North Star.
A few of the many concepts that can be demonstrated with this model are:
- The reason for the occurrence of night and day
- The variation in the length of daylight
- The movement of the Earth around the sun from west to east
- Why only one side of the moon is seen from the Earth
- How eclipses of the sun and moon occur
- Cause of the phases of the moon
These are but a few of the many basic phenomena which can be explained and demonstrated with either of these models. An instruction book, Elementary Planetariums, is included.
Height: 12"
Arm length: 17"
Sun: 5 3/4"
Earth: 4" |
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Earth Sciences 
