Use light globe for brightness demo. Why are stars so small - use string to show angles and Earth. How big are stars. This is an ambiguous question. Apparent Size Angular size is measured in degrees .
Stars are big.
Antares is over 100 million miles across. Use variac to demo why stars have different colors. Groups of stars are called clusters. Big Dipper is also in Ursa Major Open Cluster. Show Milky Way Model.