In words describe how the changes position of the sun moon and earth lead to the different moon phases

As the Sun sets, the moon rises with the tide that faces the Earth fully exposed to sunlight. The moon has phases because of its orbit to Earth which causes the portion we see illuminated to change. The new moon occurs when the moon is positioned  between the earth and the sun. at full moon and third quarter or called as the half moon, it happens when the moon is at a 90 degree angle with respect to the earth and the sun. crescent refers to the moon that is less than half illuminated by the sun. gibbous refers to more than half illuminated by the sun. waxing means growing or expanding in illumination and waning means shrinking or decreasing in illumination.

in the analysis of systems that involve fluid flow, we frequently encounter the combination of properties u and pv.