Seasons Model Instructions
From GeoMod
Model showing an idealized Earth rotating around the Sun to illustrate the how Earth-Sun relationships result in seasons seasons. Two half-spheres on the surface of the Earth change colors with time of day to show day length.
Contents |
Download Software
Download software
| Operating System | Download |
|---|---|
| All OSs (with VPython installed) | The Model Code |
| Windows XP and Vista installer | orbit_earth_sun16_GeoMod.exe (2.9 Mb) |
About
Designed to illustrate the effect of axial tilt on hemispheric insolation, this conceptual model shows the Earth as a blue sphere with a few lines of longitude and latitude marked and the Sun (not to scale). There are two dots located on the surface of the planet that can be moved along lines of longitude. The user controls the rotation rate of the planet and its orbital velocity. A typical demonstration with this model would start with the Earth slowly rotating at the northern hemisphere's summer solstice. The dots on the surface change color as they move from the day to night side of the planet so they can be used to demonstrate the relationship between day length and longitude. The scene can then be tilted to view from a direction perpendicular to the plane of the ecliptic, which is useful for showing the 24 hour days above the arctic circle. The planet can then be orbited to demonstrate the equinoxes and the other solstices. With the wide variety of controls, we have found that this model works best when demonstrated by the instructor.
User's Guide: Model Controls
Play with the buttons and sliders in the control window to see what they do. You can;
- change the Earth's rotation rate and orbital rate
- control the location of the two spheres on the surface of the Earth with sliders.
- center the view on the Earth or on the Sun and orient the view parallel or perpendicular to the plane of the ecliptic.
- show arrows to show the direction of the sun from the two locations on the planet surface.
- duplicate copies of the planet with the freeze button.
Multimedia
- Demo showing the globe from different perspectives: Media:seasons-globe.mov
Notes
- The Earth's orbit around the sun is circular in the model not elliptical
