This activity takes approximately 1.5-2 hours. In the first section, students learn to classify galaxies; use their observations to answer questions about the galaxies; and then come up with their own questions about the galaxies. After going through the scientific process with scaffolding and guidance, they are more prepared to come up with their own questions and their own plan to find the answer, which is the second section.
This activity is a modified version of "Galaxy Classification," found in Lecture-Tutorials for Introductory Astronomy by Edward E. Prather, Timothy F. Slater, Jeffrey P. Adams, Gina Brissenden, and the CAPER team.
For more information, see the paper Slater, S.J., Slater, T.F. & Lyons, D.J. (2011) Teaching Scientific Inquiry with GalaxyZoo. The Physics Teacher, 49(2), 94-96.