The Expanding Universe Student Sheet
Origins of the Universe Unit of IMPACTT
Back to 10th Grade Student Resources for IMPACTT

In this activity, you are going to create a model of the expanding Universe.
Materials needed:
You will need one balloon, a flexible metric ruler and a paper strip for conducting measurements, a copy of this page, and a ball point pen.
Steps to take: 
1. Use the ball point pen to make 10 - 15 clear dots on the balloon.
2. Inflate the balloon! Inflate balloon with 4 medium breaths to about the size of your fist; do not over
3. Bend the end of the balloon down and paper clip it so that no air escapes.
4.Record below what happens to the dots. Be very specific - use complete sentences.
5. Observations: Write observations below.
 
 
 
 
 
 
 

6. Choose a home dot and label it H. Choose 5 other dots and label them 1 – 5. Use the edge of the paper strip to connect your home dot with each of the numbered dots so that you have 5 lines on your balloon that start from the home dot, H.

7. Measure the distance between your "home" dot and the numbered dots with a METRIC RULER. Be careful not to indent the balloon by pressing on it. Record these initial distances in the “Partially Expanded” section of your data table.

8. Now measure and record the distance between your "home" dot and the other dots with the paper strip. Calculate the differences between the two measuring techniques and record in the data table.

9. Double the size of the balloon by inflating it slowly; do not over inflate the balloon! Measure and record the data from the enlarged balloon using both tools.

10. As a class decide which measuring tool is more precise, metric ruler or paper strip. Use the data from the preferred measuring tool to complete instruction #11.

11. Calculate the change in distances between the home dot and each numbered dot when the balloon went from partially to fully expanded. Record in the last column.

12. Answer the summary questions below after completing your table.

Show units for all measurements and calculations. 

Partially Expanded
Fully Expanded
Change 
Dot
Initial Distance

from Dot 

H using the metric ruler [show units]

Initial Distance

from Dot 

H using the paper strip [show units] 

Difference

between ruler and paper strip measurements

Dot
Final Distance

from Dot 

H using the ruler 

[show units]

Final Distance

from Dot 

H using the paper strip 

[show units]

Difference

between ruler and paper strip measurements

Change from before to after (use paper strip data)
1

1
2

2
3

3
4

4
5

5

Summary Questions

a. Do the dots get larger as the balloon expands? Why do you think this is or is not so?
 
 
 
 
 
 
 
b. Which measuring tool was more accurate? Why? 
 
 
 
 
 
 
 

c. Do you think you would have had similar results if you chose another dot as your “home” dot?

 
 
 
 
 
 
 
d. Assuming the dots represent galaxies moving away from each other. What relationship exists between the speed of the galaxies moving apart and their initial distance from one another? 
 
 
 
 
 
 
 
e. What happens to the “galaxies” (numbered dots) with respect to each other? 
 
 
 
 
 
 
 
f. How does this relate to the statement, “We are the center of the universe.”