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Website
NASA

Nasa Star Child: Galaxies

For Students 3rd - 8th
This resource has two levels: one for younger viewers and one for older viewers. It surveys the basic galaxy types and provides details.
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Website
Other

University of Cambridge Cosmology: Galaxies

For Students 9th - 10th
This site from the University of Cambridge allows you to view information on spiral, elliptical, and Milky Way galaxies, as well as galaxy clusters. Provides basic facts about each one.