Astronomy: there are only 2 moon phases in which the moon cannot be seen for at least an hour or 2 while the sun is above the horizon.

name those phases and explain why we cannot see the moon during these times.

New moon, Waning crescent

Explanation:

When the sun and moon are lined in the same direction the occurrence of a new moon phase and thus the side facing the earth is not illuminated and hence its also called as crescent moon and first quarter moon and when the moon is ending or declining in the phase of waning crescent which shows only a 0.1% of the disk of the moon. This period stays form 3 am to 3 pm after this the cycle of the moon is completed. Also called as the last quarter, its visibility is also defined by the rotation of angle of the earth and the sunrays.