• 3-5: 4A/E3. Planets change their positions against the background of stars.

• 3-5: 4B/E2bc. The rotation of the earth on its axis every 24 hours produces the night-and-day cycle. To people on earth, this turning of the planet makes it seem as though the sun, moon, planets, and stars are orbiting the earth once a day.

• 9-12: 4F/H2. All motion is relative to whatever frame of reference is chosen, for there is no motionless frame from which to judge all motion.

• 9-12: 10A/H1. To someone standing on the earth, it seems as if it is large and stationary and that all other objects in the sky orbit around it. That perception was the basis for theories of how the universe is organized that prevailed for over 2,000 years.
• 9-12: 10A/H3. In the 1500s, a Polish astronomer named Copernicus suggested that all those same motions could be explained by imagining that the earth was turning around once a day and orbiting around the sun once a year. This explanation was rejected by nearly everyone because it violated common sense and required the universe to be unbelievably large. Worse, it flew in the face of the belief, universally held at the time, that the earth was at the center of the universe.

• 6-8: 11B/M1. Models are often used to think about processes that happen too slowly, too quickly, or on too small a scale to observe directly. They are also used for processes that are too vast, too complex, or too dangerous to study.
• 6-8: 11B/M4. Simulations are often useful in modeling events and processes.

A great simulation to help students understand that stars are not moving in the night sky......our planet's rotation on its axis just makes it appear so. This sim features Polaris as the focal point for investigating moving reference frames.

• Physical Sciences K-8 Astronomy Activities Unit
• Physics First Astronomy Activities Unit
• Conceptual Physics Astronomy Activities Unit
• Algebra-Based Physics Astronomy Activities Unit