"Waning" and "waxing" are used to describe the phases of the moon.Waning means a gradual describe in size and waxing means a gradual increase in size.When the moon is waning,it starts to lose its light and the dark region starts to increase until it is a new moon.When the moon is waxing,it is going from the new moon to the full moon.During,this journey,the moon starts to lose its darkness and gains light..
Determining whether the moon is waxing or waning can tell you a lot about what phase it’s in, how the tides will move, and where the moon is in relation to the Earth and the sun. It’s also helpful to know where the moon rises and sets during its different phases, in case you want to see it on a particular night. A waxing moon is in the process of increasing how much of it is lit (as observed night to night). i.e., it's headed toward being a full moon. Waning is the opposite. There are a couple ways to figure out whether the moon is waxing or waning. Although the details are slightly different depending on where you are in the world, the bulk of the method is the same.
Learn the names of the phases. The moon revolves around the Earth, and as it does, we see different angles of the moon’s illuminated surface. The moon doesn’t create its own light, but rather shines when it reflects the sun’s light. [1] As the moon transitions from new to full and back to new again, it goes through several phases, marked by its recognizable crescent and gibbous ("bulging") shapes, which are created by the moon’s own shadow.[2] The moon phases are:
New moon
Waxing crescent
First quarter
Waxing gibbous
Full moon
Waning Gibbous
Third quarter
Waning crescent
New moon[3]
Learn what the phases mean. The moon travels the same path around the Earth every month, so it goes through the same monthly phases. The phases exist because from our perspective on Earth, we observe the illuminated portion of the moon differently as it makes its way around us. Remember that half the moon is always illuminated by the sun: it’s our vantage point on Earth that changes and determines what phase we see.
During the new moon, the moon is between the Earth and the sun, and is therefore not illuminated at all from our perspective. At this time, the moon’s illuminated side completely faces the sun, and we see the side that’s in full shadow.
During the first quarter, we see half of the moon’s illuminated side and half of the moon’s shadowed side. The same is true in the third quarter, except the sides we see are reversed.[5]
When the moon appears full, we see its full illuminated half, while the side that’s in complete shadow faces out into space.
After the full moon, the moon continues its journey back to its original position between the Earth and the sun, which is another new moon.
It takes the moon a little over 27.32 days to complete one full revolution around the Earth. However, a full lunar month (from new moon to new moon) is 29.5 days, because that’s how long it takes the moon to return to its position between the sun and Earth