The Astronomy Center has provided educational resources to introductory astronomy educators since 2003. Over the past 20 years, the rapid pace of discovery has rendered some of our linked resources obsolete. Thus, the Astronomy Center will be decommissioned on March 1, 2022. Our highest quality resources will be retained on ComPADRE.org.
The Solar and Lunar Eclipse model simulates the occurrences of solar and lunar eclipses. Moon's orbital inclination of 5.145 degrees with respect to the ecliptic (the Earth-Sun orbital plane) is what is responsible for solar and lunar eclipses not occurring every month. In addition, the orbital plane of Moon precesses every 8.85 years, the so-called precession of the apsides. The inclination and the motion of Moon and Earth are depicted (the size of Sun, Earth, and Moon and the size of Moon's orbit are not shown to scale). The illuminated sides of Earth and Moon and the regions of possible eclipses (in yellow and green) are also depicted. In the Ecliptic View, the motion of Sun and Moon across the sky (+/- 7 degrees from the ecliptic) are shown. Moon's phase is shown and solar and lunar eclipses can occur on the ecliptic when Earth, Sun, and Moon line up properly.
Please note that this resource requires
at least version 1.5 of Java (JRE).
This model of the solar system can explain eclipses of the sun and the moon. Earth's spin axis is fixed in direction over the short-term but tilted relative to its orbit around the sun. The seasons are a result of that tilt and are caused by the differential intensity of sunlight on different areas of Earth across the year. (6-8)
Kepler's laws describe common features of the motions of orbiting objects, including their elliptical paths around the sun. Orbits may change due to the gravitational effects from, or collisions with, other objects in the solar system. (9-12)
Crosscutting Concepts (K-12)
Systems and System Models (K-12)
When investigating or describing a system, the boundaries and initial conditions of the system need to be defined and their inputs and outputs analyzed and described using models. (9-12)
Models can be used to predict the behavior of a system, but these predictions have limited precision and reliability due to the assumptions and approximations inherent in models. (9-12)
NGSS Science and Engineering Practices (K-12)
Developing and Using Models (K-12)
Modeling in 9–12 builds on K–8 and progresses to using, synthesizing, and developing models to predict and show relationships among variables between systems and their components in the natural and designed worlds. (9-12)
Use a model to predict the relationships between systems or between components of a system. (9-12)
Belloni, M., & Timberlake, T. (2009). Solar and Lunar Eclipse Model (Version 1.0) [Computer software]. Retrieved January 31, 2023, from https://www.compadre.org/Repository/document/ServeFile.cfm?ID=9640&DocID=1407
%0 Computer Program %A Belloni, Mario %A Timberlake, Todd %D November 13, 2009 %T Solar and Lunar Eclipse Model %7 1.0 %8 November 13, 2009 %U https://www.compadre.org/Repository/document/ServeFile.cfm?ID=9640&DocID=1407
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