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Galaxies and Nebulae

Each activity or resource is labeled by access mode:

Requires computer access
Requires downloading from the Web
$$ Order materials and supplies
Main Topics & Concepts
  • Galaxies are classified as elliptical, spiral, barred spiral, or irregular
  • Some galaxies are irregular, possibly because of gravitational interactions or "collisions" with other galaxies.
  • Most of the universe's visible mass is in galaxies and their outlying stellar clusters.
This topic applies to California state standards 4a in 8th grade Earth Science and standards 2a and 2b in 9th grade Earth Science. 
Science Probe Text
Science Probe I § 15.3 Galaxies and Star Clusters

Activities & Lessons
Activity Access Description

Universe at Your Fingertips

Activity H3: How Many Stars?


Students using a measuring box or cylinder count grains of sand to develop a sense of the 200 billion stars in our galaxy. 

Classifying Galaxies

Students learn galaxy morphology (classification by appearance) and how to use the Hubble tuning fork diagram to organize the forms.  Uses Java.

Hidden Lives of Galaxies: Activity 6b

Extension: Weighing a Galaxy.

Imagine the Universe

Booklet available online as HTML or PDF, with activities, standards alignment and  background.

Math based scaling exercise leads students to calculate the mass of a galaxy using Newton's 2nd law and the law of gravitation. Printable worksheet. Teacher's Background: Sections A & B, Hidden Objects and Hidden Mass.

Hubble Deep Field Academy

HST Education

web students are guided through interactive tasks in proportional sampling, galaxy classification, and

More Universe at Your Fingertips

Galaxy Sorting


Student groups are given 20 galaxy images to sort into categories of their own devising.  The groups compare notes about their criteria and learn about what the different visual characteristics of galaxies imply.

*Astronomical Society of the Pacific. Ordering info $$

**Science Education Gateway for teachers


Resources Access Description
Hubble Photo Galleries: Galaxies web Spectacular and compelling images are linked to science pages about why these galaxies are special.
Hubble Photo Galleries: Nebulae web More spectacular pictures--you pretty much have to be blind not to want to look at these. But don't let this distract you from checking the information pages ("Learn more" links) about the awesome physical processes taking place.
The Web Nebulae

Bill Arnett

web Beautiful pictures of these immense clouds, star clusters-to-be. However the links to their sources don't necessarily lead directly to information about the images.
Messier Catalog web Catalog of galaxies, nebulae, and clusters

Hubble Space Telescope

A number of interactive games around identifying and classifying galaxies from their Hubble images.  Requires a ShockWave player (downloads automatically)