Benchmark 4A
The Physical Setting: The Universe
Grades K-2, page 62

The moon looks a little different every day, but looks the same again about every four weeks.

NSES Content Standard D 
Earth and Space Science: Changes in the Earth and sky 
Grades K-4, page 134 
Objects in the sky have patterns of movement. The sun, for example, appears to move across the sky in the same way every day, but its path changes slowly over the seasons. The moon moves across the sky on a daily basis much like the sun. The observable shape of the moon changes from day to day in a cycle that lasts about a month.