Question

1. think and discuss: waxing means \growing\ and waning means \shrinking.\

a. seen from the north pole, which side of a waxing moon is illuminated?
b. which side is illuminated when the moon is waning?
c. suppose you see a crescent moon. how do you know if it is waxing or waning?

Explanation:

• A: When the Moon is waxing (growing in illumination as seen from Earth), from the perspective of the North Pole (assuming a "standard" view where we consider the Moon's orbit and illumination similar to how we observe from Earth - with the Sun as the light source), the right - hand side of the waxing Moon is illuminated. This is because as the Moon moves in its orbit around the Earth (in a counter - clockwise direction as seen from above the North Pole), the side that is "gaining" illumination (waxing) is the right side.
• B: When the Moon is waning (shrinking in illumination as seen from Earth), the left - hand side is illuminated. As the Moon continues its orbit and moves past the full - Moon phase, the side that is "losing" illumination (waning) is the left side.
• C: If you see a crescent Moon, you can tell if it is waxing or waning by its orientation. In the Northern Hemisphere (a common reference for such observations), a waxing crescent Moon will have the "horns" (the dark, un - illuminated parts) pointing to the left, and the illuminated part on the right. A waning crescent Moon will have the "horns" pointing to the right, and the illuminated part on the left. This is based on the Moon's orbital motion and the direction of illumination from the Sun.

Answer:

A. The right - hand side.
B. The left - hand side.
C. In the Northern Hemisphere, a waxing crescent has horns pointing left (illuminated on the right), and a waning crescent has horns pointing right (illuminated on the left).