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Classifying Galaxies

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Posted over 2 years ago. thuddy:

I'm having trouble with the attachment for the Classifying Galaxies Powerpoint. I've tried to download the powerpoint, but after unzipping it they are all .xml docs which are just a bunch of gobbledegook. Is there a secret to getting the powerpoint working? I'm really excited to use it in my class. Otherwise this is a great activity that I'll use in my class! Thanks!


This lesson aims to introduce students to the concept of sorting objects into groups and to the idea that although individual members differ in many ways they have enough features in common to be recognised as a group (ie/ a species). It should be used as an precursor to lessons that introduce classification schemes for living things (ie/ plants/animals, vertebrates/invertebrates, mammals/birds/fish/reptiles/amphibians).

The class will also be given the opportunity to participate in an authentic research project, Galaxy Zoo. The classifications made by the group during the lesson will be help scientists gather information about the different types of galaxies in the universe.

Materials, Resources and Preparation
  1. Plate (spiral galaxies)
  2. Football (ellipticals)
  3. Rugby ball (ellipticals)

Note: In order to sign up for a Zooniverse account, each pair of students will need an email address. The email address is the only information that they are required to give, they will need to create a login name, but they do not have to give their actual names unless they wish to do so. Email addresses are never shared by the Zooniverse with any other organisation.

Additional Notes

Homework: Design a key to classify members of the class.

Further activities: Make your own Hubble Tuning fork: http://lcogt.net/en/education/activity/create-hubble-tuning-fork-diagram

  • Sort galaxies into groups.
  • Use a key to classify galaxies.
  • Participate in an authentic research project.

Children should learn:

  • that although individual members of a group differ in many ways they have features in common.
  • to classify galaxies into groups which have features in common, giving reasons.

Scientific enquiry:

  • consider why classification is important
  • make qualitative observations and record these in a variety of ways


Science at key stage 3 (Year 7) Unit 7D: Variation and classification Section 8: a. How can we sort things into groups?

Student Prerequisites
  • An understanding that our star is one of many in a galaxy.
  • There are many galaxies.
Teacher Prerequisites

It would be helpful to have familiarised yourself with the galaxyzoo.org website.

Student Misconceptions

Extension: Group Data Collection

One of each pair should visit the white/chalk board to fill in a tally chart of their results.

  • Spirals
  • Barred Spirals
  • Ellipticals
  • Irregular
  • Edge on Spirals

Homework: Make a bar chart of the results of today’s investigation.


Activity 1: Galaxy Zoo Classification Cards Duration: 10 minutes Team size: 3-4 students per team. Materials: 30 galaxy images on cards.

Teaching Sequence:

  1. Give each group a set of cards. Ask them to sort them into at least 2 and at most 6 different groups.
  2. Ask a member of each team to stand up and describe the differences between each of their groups. Keep a note of the different groups on the board.
  3. Decide as a class on what groups would be best to have. This may be colours, shapes, or features.
  4. What so all galaxies have in common?


  1. When deciding upon what groups to have it would be worth steering the class away from using ‘size’ to differentiate between galaxies. It might be worth explaining to the class that the images are at different ‘zoom levels’. Some of the galaxies look bigger as they are closer, so we need more information to sort them based on ‘size’. Of course it is worth noting that ‘size’ is an important consideration in the study of galaxies, hence you do have ‘dwarf spiral’ and ‘dwarf ellipticals’, but without further information about the images it would be impossible.
  2. As a whole, ellipticals galaxies tend to be reddish and spiral galaxies tend to be blueish. This is because spirals have many young, hot stars that are blue and ellipticals have many old stars that are red.
Main Lesson

Activity 2: Galaxy Zoo Duration: 30 minutes Team size: 2 students per team. Materials: Access to the Galaxy Zoo Website

Teaching Sequence:

Introduce ellipticals, spirals and irregular galaxies to the class. 1. Demonstrate how spirals are disk shaped, like a plate. Ellipticals are shaped like balls. Explain that these are the two main groups that scientists divide galaxies into. 2. Ask everyone to choose and hold up a spiral galaxy from their pack of cards. Repeat for ellipticals. 3. Spiral galaxies look very different when viewed edge on. 4. Spiral galaxies can be split into two ‘subsets’ depending on whether or not they have a bar. 5. Spiral galaxies can have 1, 2 or more spiral arms. Also it isn’t possible to tell if a spiral galaxy has a bar or not if viewed from edge on. 6. Ellipticals can be round like a football or more like a rugby ball.

Introduce Galaxy Zoo to the Class

  1. What are scientists hoping to achieve with Galaxy Zoo.
  • The aim of the project is to collect information on the shape of the galaxies.
  • Scientists want to see how the mix of galaxies has changed over time.
  • More stars were forming back then, so does that mean there should more spirals galaxies?
  • Or will we find ellipticals that have star formation as we travel back in time?
  • This will help scientists understand how galaxies form.
  • Are there any new galaxy types out there waiting to be discovered? (Green Pea Galaxies were not know to exist until “Zooites” discovered them when classifying galaxies on the Galaxy Zoo website. Professional astronomers had never noticed them! They are thought to be a previously unknown type of ultra compact galaxy and are of great interest to astronomers.
  1. First you will need to register for a Zooniverse account.
  2. You will need to put in your email address and choose a login name. You do not need to give your name unless you want to, but you will also need to make up a password.
  3. Once you have registered for an account and logged in, you can start classifying galaxies.
  4. As you classify 10 galaxies, you should make observation notes on the worksheet. Also draw a quick sketch of the galaxy.
  5. Add each galaxy to your ‘favourites’.


  1. Adding galaxies to ‘favourites’ will allow the teacher to check that each pair has actually classified 10 galaxies. You could also set additional classifying as homework, then check in class if the classifying has been completed.
  2. For more details about the science behind Galaxy Zoo please see: http://www.galaxyzoo.org/science

Activity 3: Classifying your galaxies. Duration: 10 minutes Team size: 2 students per team. Materials: Galaxy Zoo Key

Teaching Sequence:

  1. Using the Galaxy Zoo Key to help you, classify your 10 galaxies.