1. Describe the difference between a solar day and a sidereal day, and state why they are different. Use a diagram to explain your answer.

2. Explain why it is convenient to have the Earth divided into time zones, rather than using local solar time at every location.

3. A constellation is a grouping of stars that appear near each other in the sky when viewed from Earth. Are the stars in a constellation all the same distance from us? Explain.

4. Explain how our seasons would be different if the Earth's axis were not tilted (that is, if the axis were perpendicular to the Earth's orbital plane). What would the seasons be like if the Earth's axis were tipped 90º instead of 23½º?

5. Our calendar, like many ancient ones, has the year divided into months that are based on the motions of the Moon. Is the sidereal month or the lunar month used in these calendars? Explain.

6. Explain why, on certain nights, the Moon is never visible at all.

7. If a quarter Moon is already up when the Sun sets, is it first or third quarter? Use a diagram to explain your answer.

8. What is the Moon's phase if it is at the zenith at 10am? What is the Moon's phase if it is rising at 10am? What is the Moon's phase if it is setting at 10am? Use a diagram to explain your answers