Proper Pair Pre- and Post-Assessments
Quizzes for use before and after the Proper Pair Worksheet III is used are provided for assessment of
the effectiveness of student learning. Generally, the pre-quiz should be given after the students have
seen the concepts of parallax and proper motion using Worksheet I, but before they have explored the
Proper Pair website for Worksheet III.
Pre-Quiz (Quiz 1)
For the pre-quiz, students are shown a color image of the Jewelbox star cluster, and asked to suggest
methods for identifying which stars are members of the star cluster and for determining the distance to
the star cluster.
To save toner, we recommend that the image of the Jewelbox be projected, rather than duplicated for
each student. The image of the Jewelbox star cluster can be found through the following websites:
National Optical Astronomy Observatory:
http://www.noao.edu/education/jewels/image.html
http://www.noao.edu/image_gallery/html/im0423.html
Astronomy Picture of the Day:
http://apod.nasa.gov/apod/ap080803.html
Students who understand the concepts of parallax and proper motion should indicate that cluster
members should all have similar parallaxes and proper motions, while stars that are not members of the
cluster will likely have different parallaxes and proper motions.
Other methods that students might mention include that cluster members will likely be grouped
together on the sky, or that cluster members will form a tight sequence in a color-magnitude diagram.
Post-Quiz (Quiz 2)
For the post quiz, students are given an image similar to what is seen in the Proper Pair web tool (to
save toner, the image is shown as black on white, rather than with white stars on a dark background).
Students are asked to identify which stars are probable members of the cluster, based on the direction
of their proper motion vectors, and to discuss what additional information should be used to confirm
membership (the magnitude of the proper motion vector). Finally, students are asked what
measurement would be needed to confirm that all stars are at the same distance (parallax).
Star Cluster Quiz 1
Name______________________________
On the screen is an image of the star cluster known as the “Jewelbox.” The Jewelbox is a nearby,
young cluster located in the southern sky, and it contains young, massive, hot, blue stars.
The cluster lies in a direction in which many stars are observed, not only members of the cluster but
also stars at larger and smaller distances than the cluster itself. Astronomers are faced with the task of
determining which stars are members of the cluster and which are not.
1.
Briefly describe what observations would help to determine which stars are members of the star
cluster and which stars are not, and how those observations could be used to discriminate between
members and non-members. Suggest as many techniques as you can.
2. What measurement is necessary to determine the distance of a star and which stars would you expect
to be at similar distances?
Star Cluster Quiz 2
Name ___________________________
The star field above indicates the direction of motion in the sky (proper motion) of each star in a small
region that contains a star cluster. Several of the stars have been labeled with the letters A-L.
2.
List the stars that are probable members of the star cluster.
2. Aside from the indicated direction of motion, what additional information would be needed to
determine whether each star in the star field is actually a member?
3. Which stars would you expect to be at similar distances and what measurement is necessary to
determine the distance?