ISP 205, Section 3, Spring 2003

ACTIVITY: EXPANSION of the UNIVERSE

Work in groups of THREE. Each group needs one balloon and one ruler. One person handles the balloon, one person marks and measures, and one person records the results. Submit one activity report for all of you.



Name: _______________________________     Student Number: ______________




Name: _______________________________     Student Number: ______________
 



Name: _______________________________     Student Number: ______________

In this activity we model the UNIVERSE as the TWO-DIMENSIONAL SURFACE of a balloon. Blow up the balloon to about a 4 inch diameter. Twist the neck and hold it closed so that no air escapes, but do NOT make a permanent knot because you will need to blow it up some more. Make SIX marks on its surface to represent clusters of galaxies and label them A-F. [Avoid placing any near the neck of the balloon.]

A. Measure and record the distances (in cm) from cluster A to each of the other 5 clusters. The DISTANCE between two points on the surface of the balloon is the SHORTEST distance between them along a path on the surface of the balloon.

B. Repeat step 1 measuring the distances (in cm) from cluster E to each of the other clusters.

C. Now blow up the balloon up more, to a diameter of about 8 inches. Measure the distances between the same clusters again and record them.

D. Calculate the increase in the distance and record that as well.

Use the chart provided on the other side of this page

















                Clusters   Distance    Distance   Change in
                           (small)     (large)    Distance
                             (cm)        (cm)       (cm)


                A - B      --------    --------   --------


                A - C      --------    --------   --------


                A - D      --------    --------   --------


                A - E      --------    --------   --------


                A - F      --------    --------   --------



                Clusters   Distance    Distance   Change in
                           (small)     (large)    Distance
                             (cm)        (cm)       (cm)


                E - A      --------    --------   --------


                E - B      --------    --------   --------


                E - C      --------    --------   --------


                E - D      --------    --------   --------


                E - F      --------    --------   --------

  1. Are all the other clusters moving away from cluster A? 
                                YES _____      NO  ____

  2. Are all the other clusters moving away from cluster E? 
                                YES _____      NO  ____

  3. Is there a cluster that could be considered to be at the center of the universe as represented by the surface of the balloon? 
                                YES ____      NO  _____
  4. Finally, on the graph below plot the change in distance verses the initial distance for both sets of measurements. Use one symbol for the measurements from cluster A and another for the measurements from cluster E.
    Draw the best straight line you can that comes closest to the most points. Is a straight line a good representation of your measurements? 
                                YES _____      NO  ____
    Visions of the Universe
    Bob Stein's home page , email: steinr@pilot.msu.edu