Michigan Test for Teacher Certification (MTTC) Secondary Integrated Science Practice test

Which phase represents the last stage before the moon becomes completely invisible?

1. Waning crescent

2. Full moon

3. First quarter

4. Waxing gibbous

The correct answer is: Waning crescent

The waning crescent phase represents the last stage before the moon becomes completely invisible, which is known as the new moon. During the waning crescent stage, the illuminated portion of the moon is decreasing, appearing as a thin sliver in the sky. This phase occurs after the third quarter, as the moon continues to move in its orbit around the Earth, transitioning towards the new moon phase where it is no longer visible from Earth due to the alignment of the sun, Earth, and moon. In contrast, the full moon phase represents the time when the moon is fully illuminated, while the first quarter and waxing gibbous phases indicate the moon is increasing in illumination rather than decreasing. Thus, the waning crescent is specifically identified as the phase just before the moon disappears entirely from our view.