- Classifying Galaxies
Teacher's Page
Classifying Galaxies: A lesson on how
Galaxies are classified by shape.
Lesson Plan Content
TABLE OF CONTENTS:
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The purpose of this lesson is twofold:
- 1)You will become familiar with the Hubble Tuning Fork Diagram, a
system of classification for galaxies invented in the 1920's by the noted astronomer Edwin
Hubble. It is still in use today.
- 2) You will practice the technique, useful in science, of engaging
a scheme or plan to classify objects in a group. In this lesson you will be able to
look at images of different kinds of galaxies, taken by the world's best telescopes. In
most high school astronomy texts and in some earth science texts, the Hubble Tuning Fork
Diagram is presented as a way to classify, or put into groups, the various types of
galaxies observed in space.
If you are not studying galaxies, this lesson still might be
useful. It follows, in an organized way, the process by which scientists group or classify
objects in nature. The lesson is designed to be used either way.
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Student Objectives
Students will :
1- Examine pictures of galaxies.
2- Discover that these pictures have been
arranged according to a scheme or plan laid out by Edwin Hubble in the 1920's.
3- Practice using the scheme, called the Hubble Tuning
Fork Diagram, to classify unidentified galaxies, as presented in pictures.
4- Display the knowledge gained during this activity
using a worksheet presented by the teacher.
5- Demonstrate an understanding of what
"classification" means as it relates to science.
6- Examine an unidentified galaxy image and attempt to
classify it based on the methods that they have learned.
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Procedure
Teacher Component
In any study of "the Universe", the subject of galaxies
normally will be covered by the teacher. If the teacher decides to go into more detail,
and to present the idea of different types of galaxies that exist in the universe, this
activity would be an excellent follow-up to an initial teacher introduction. We see this
activity as a group workstation activity involving one group or many groups. It could be
used as an extension of a classroom presentation. It also could be used as a review, if
the Hubble Tuning Fork Diagram is covered by the teacher.
It has been designed so that just two main ideas are presented:
1) the scheme of Edwin Hubble's Tuning Fork Diagram.
2) practice in using his scheme as an example of how scientists
attempt to classify objects in nature.
Students will begin the lesson at the blinking message: "".
Students will indicate their mastery of the objectives by responding to questions on a
paper worksheet. The worksheet should be copied and printed, and handed to students to
complete as they participate in the activity. A worksheet you may use is provided at the
end of this section, followed by a copy of the worksheet with answers (Teacher Key) for
your use.
One way to print the student worksheet for this lesson is to
click on "File" at the top of your web-browser screen, and select
"Print" if your computer has a printer available. If you do not have a printer
accessible from your browser, you can click on "File", and select "Save
as" to save the worksheet to a floppy disk. You can then use the file in a word
processor.
There are many fascinating links to this subject that we have
found. We would particularly like to recommend this one: "Cosmic
Classifier", one of four astronomy activities at the "Hubble
Deep Field Academy". We
mention it in the student activity specifically as an option, but you should take a look
at it. You may want to assign it as well. We think it is a perfect extension and
follow-up of our simple activity. It is not particularly difficult, and would be
appropriate for upper elementary or middle school students. NOTE: The "Cosmic
Classifier" activity will require your computer to be able to use Adobe Acrobat
Reader, which is available for free download at the site.
There are other excellent links which are noted and described
under "Extensions" in the Table of Contents.
Student Component
Students will begin the lesson at the blinking message: "".
Students will indicate their mastery of the objectives by responding to questions on a
paper worksheet.
Lesson Plan Assessment
1. Students will mark their progress by answering questions on a
worksheet . This worksheet is provided online for teachers to copy. Teachers may also copy
an answer key, also provided online, to check on students' progress.
2. Students will use an ONLINE activity to classify galaxies by
placing images of galaxies on the Hubble Tuning Fork diagram, using the classification
scheme developed by Edwin Hubble.
3. Students will examine an unidentified galaxy image, and
attempt to classify it based on the methods that they have learned.
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Lesson Plan Ties To Science Framework
Link to Science
Standards of Learning for Virginia
Project 2061:
Benchmarks for Science Literacy: Recommendations of what all
students should know and be able to do in science, mathematics, and technology by the time
they graduate from high school.
- This nationwide study is one of the major frameworks and we
include specific references from that study below for grades 5-9:
- The universe contains many billions of galaxies, and each galaxy
contains many billions of stars.
- Increasingly sophisticated technology is used to learn about the
universe. Visual, radio, and x-ray telescopes collect information; mathematical models are
used in studying evidence from many sources in order to form a scientific account of the
universe.
- Scientists try to observe as wide a range of natural occurrences
as possible to be able to discern patterns.
- Tables, graphs, and diagrams can show how values and/or objects of
one type are related to values and/or objects of another.
- Some aspects of reasoning have fairly rigid rules for what makes
sense; other aspects don't. If people have rules that always hold, and good information
about a particular situation, then logic can help them to figure out what is true about
it. This kind of logic requires care in the use of key words such as if, and,
not, or, all and some. For example, people are using incorrect logic when they
make a statement such as "If A is true, then B is true; but A isn't true, therefore B
isn't true either".
- Sometimes people invent a general rule to explain how something
works by summarizing observations.
- All scientific investigations usually involve the collection of
relevant evidence, the use of logical reasoning, and the application of imagination
in devising hypotheses and explanations to make sense of the collected evidence .
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Lesson Plan References
- Pasachoff, Jay M. "Journey Through The Universe, 1994
Version". 1992. Sanders College Publishing. Harcourt Brace Jovanovich. New York.
- Sandage, Allan. "The Hubble Atlas of Galaxies".
1961. Carnegie Institution of Washington. Washington, D.C.
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Related Lesson Plans
- Hubble
Deep Field Academy: Four activities related to galaxy astronomy:
- 1- Stellar
Statistician: uses the Hubble Deep Field Image in an exercise to teach about sampling.
- 2- Cosmic
Classifiers: a very visually appealing activity with more complicated galaxy
identification involving color, size and shape.
- 3- Galactic
Guide: an activity on determining the distances to galaxies.
- 4- Universal
Graduate: a review quiz on concepts presented in the four lessons above.
- Sky Den -
an excellent site with basic lessons and multiple links on these topics:
- 1.Our Solar
System
- 2.Galaxies
- 3.Clusters,
and Beyond...
- 4.Gravity
- 5.The Expanding
Universe
- 6.The Big Bang
- 7.The Fate of
Our Universe
- 8.Weighing
the Universe
- 9.Formation
of a Galaxy
- 10.The Doppler
Effect
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comments to George & Jane Hastings
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"Classifying Galaxies" is
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This page last updated February 11, 2000