He or she would need to do more research on their experiment before examining.
Whites and free blacks from the North were most often the teachers in Freedmen's Bureau schools.
Freedmen's Bureau was a sort of a shelter from former slaves who had nowhere else to go to. They could come to the Bureau and stay there, get some food and clothing, and later, even education. Schools were opened in the Bureau, and many white people from the North (as well as educated black former slaves) came here to educate them.
The US is divided into four different time zones.
The moon is nothing but a oight mirror of the sun. So some light from the sun lights a part of the moon(depending on it's position) . On different days the moon has different position(taking sun as reference) so it is diferently lighted. This creates the phases