The size of a star has a direct effect on its apparent brightness, which can be demonstrated by comparing Deneb, which is bright but very far away, to bright but very near stars in the summer triangle, such as Vega and Altair. Perhaps the students should be shown the Hertzsprung-Russell diagram, which is the heart of stellar astronomy. After all, if you understand this diagram, you can understand about half of everything that is said in a professional meeting of astronomers and astrophysicists. The H-R diagram as a unifying principle in astronomy is as important as natural selection is in the life sciences. This is a planetarium activity taken directly from the Spitz manual and can be done quantitatively with round cardboard viewing tubes for each student.
Gravity always gives rise to pairs of motion in the cosmos.
It is appropriate to turn on the ecliptic coordinate system, something unique to a planetarium. The sixth grade curriculum is so rich in things that can best be done in a planetarium that several visits and detailed coordination with the classroom teacher would be very helpful. In the seventh grade the theme of the science program is life science. Three different hour-length programs are available for seventh graders with an emphasis on life science. Living in Space explores what humans have to do to adjust to weightlessness and the absence of air and a comfortable temperature.