Activity # 5 - Open Clusters versus Globular Clusters
In this activity, students will describe similarities and differences between galactic star clusters and globular clusters.
Show students Transparency #5: M37/M80, compare the open cluster M37 to the globular cluster M80 (See http://imagine.gsfc.nasa.gov/docs/teachers/galaxies/transparencies/ for transparency.) Also review the material in section C on the components of a galaxy.
See Student Worksheet
Worksheet Answers/Assessment Guide
Answers should include the following similarities: both contain numerous red stars, and colored stars. Globular clusters contain older stars. Stars near the center tend to be brighter. The cluster contains hundreds to thousands of stars. The stars appear closer together. Open cluster stars appear scattered. The blue stars are more visible. Open clusters contain hundreds of stars, many which are bright, young, and blue.
The analogy between a globular cluster and bees swarming about a beehive can be appropriate in the depiction of many stars moving about a common center. The analogy can be inappropriate in that the stars move slowly, and in paths determined by the gravitational forces of the stars in the cluster. The bees, on the other hand, are "self-propelled" and move more randomly.