The Bridge V Learning Edition 1 ; our solar system | Page 54

Step 1
Tell students: Above diagram shows a mosaic of 40 galaxies. These images were taken with the
Hubble Space Telescope and show the variety of shapes that galaxies can have. When
astronomer Edwin Hubble first started studying these various types of galaxies in the 1920s, he
developed a way to organize and categorize them. He created a classification scheme in which
he grouped similar galaxies together.
Your job is to do the same thing. In the following chart, invent your own galaxy types and
provide a description of these galaxy types and three examples for each one.
Fill in the table in the worksheet.
Step 2
Discussion: Ask students to share their classification schemes with each other. Suggested points
of discussion:
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What are significant similarities between schemes?
Significant differences?
Arguments about how to classify particular galaxies?
Why did students decide to design their schemes the way they did?
What are other completely different types of schemes you could devise, e.g., if you had
different data on the same galaxies?
ˆ Why is it important (or not) to classify objects we discover?
ˆ Might classification schemes be changed over time?
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