Lab Assignment 03 - Phases of the Moon

Lab Assignment 03 – Phases of the Moon: In this lab, you will investigate the phases of the moon. The diagram below shows a view of the Earth and Moon from above, with the suns rays coming in from the right. This is a useful orientation to help you understand how the phases occur. There are a few important things to note: - Note that one-half of the moon is illuminated at any given time (as seen from above). - The phases of the moon we see are a result of the angle of view from Earth as the Moon orbits around us. - Each phase of the moon is visible from Earth at different times of the day. o If you were standing on the Earth at the marked locations, your local time of day would be as indicated (Can you visualize the angle of the sun from that location?) o The phase of the moon would reach it’s transit (highest point) directly across from the corresponding time of day. The rise and set would mark out a 180-degree angle from that time. Part 1 : Complete the table below using this diagram, and possibly a model system to help you get the shadows correct (lamp + some sort of ball). Draw/shade the phase of the moon, and indicate the rise/transit/set time for each phase.

1. 2. 3. 4. 5. 6. 7. 8. Phase: Full moon Rise time: 6pm Transit time: midnight Set time: 6am Phase: Waning gibbous Rise time: 9pm Transit time: 3am Set time: 9am Phase: First Quarter Rise time: Noon Transit time: 6pm Set time: Midnight Phase: Waxing Crecent Rise time: 9am Transit time: 3pm Set time: 9pm Phase: New Moon Rise time: 6am Transit time: Noon Set time: 6pm Phase: Waning crescent Rise time: 3am Transit time: 9am Set time: 3pm Phase: Third Quarter Rise time: midnight Transit time: 6am Set time: noon Phase: Waxing gibbous Rise time: 3pm Transit time: 9pm Set time: 3am

5. Suppose you see the moon during a gibbous phase. How could you determine if it is waxing or waning? (hint: what time are you seeing it) If you watch the moon during a gibbous phase, you can use the time of observation to determine if it is waxing or waning. When the moon is in its gibbous phase, which occurs in the evening after sunset, it is waxing. This indicates that it is transitioning from a new moon to a full moon. The moon's luminous area is growing as it moves from darkness (new moon) to light (full moon). On the other hand, if you witness a gibbous phase of the moon early in the morning, it is declining. This suggests that a new moon is approaching after the current full moon. The moon is getting less and less lighted as it moves from full light to dark. Hence, during the gibbous phase, the important thing to note is whether the moon is in the eastern sky after sunset (waxing) or in the western sky before daybreak (waning). 6. Let’s say you see a crescent moon in the evening, just before sundown. You measure the angle between the moon and the sun to be about 75 degrees. How many days will it be until the moon reaches first quarter phase (first quarter is at a 90- degree angle from the sun)? The moon travels across the sky by nearly 13.22 degrees every day as it round the Earth, with a lunar month lasting roughly 29.5 days. The moon moves 15 degrees (90 degrees - 75 degrees) from the sun in how many days? This is because the moon is at a 90-degree angle to the sun during the first quarter phase. 15 degrees -------------------------- ≈1.13 days 13.22 degrees/day

7. What phase is the moon currently in? (You can determine this a number of ways – go outside and look for the moon, use the internet, etc.) Currently in the waning gibbous phase What time of day would you have to go outside to see the moon in its current phase? Before dawn, in the early morning, is the ideal time to see a waning gibbous moon. In the predawn hours, waning gibbous moons can be seen in the western sky. How long until the Next full moon? Approximately 18 days