PROBLEM: How are galaxies classified?

PREDICTION: 

PROCEDURE:  

Part I. Answer the following questions:

1. Galaxies are a group of________________________________________.
2. The galaxies stay together because_______________________________. 
3. Galaxies are part of the ________________________________________. 

Part II. Label the following diagram using the terms stars, arms, dust, and nucleus

Part III. On the following pages there are actual pictures of different galaxies. Group the pictures using the classification explained by your teacher. Cut the pictures out, paste them into their groupings, and label them. In the space below, draw and/or describe the characteristics of each group.

Do you see any relationship between the shape of the galaxies and how they may have evolved? Look closely at the shapes.

Look on a celestial globe. How can you identify a galaxy from a star?

CONCLUSION: Do all the pictures of galaxies fit into defined groups or do you think the classification of galaxies is nebula (not clear)!