What better place to draw a model of the galaxy than on a partially inflated balloon? Students who have scissors instead of hands are excused from this activity. Register to explore the whole course here: https://school.bighistoryproject.com/bhplive?WT.mc_id=Slideshare12202017

1. TEACHER MATERIALS
Page 1
BIG BANG BALLOON WORKSHEET
BIG HISTORY PROJECT / LESSON 2.3 ACTIVITY
Purpose
In this activity, students will create a model to better understand how the Universe is expanding.
Process
Have students get into small groups. Tell them they’re going to use balloons to better understand one of the analogies Fraser used for the expanding Universe. Tell students to inflate
their balloons until they about 4 inches (10 cm) in diameter, and then pinch the balloons closed with their fingers (be sure they don’t tie off the balloons).
Someone else in the group will use a felt-tip marker to make five dots on the balloon, being sure to scatter the dots all over its surface. Label one dot “MW” and the others “A,” “B,”
“C,” and “D. » “MW” stands for our home in the Milky Way galaxy, and the other letters represent other galaxies in the Universe.
Working together, and without letting air out of the balloon, have students use the string and ruler to measure the distance from the “MW” dot to each other dot. Have someone in
the group record the distances in the Big Bang Balloon Worksheet table under the Time 1 heading.
Now, tell the students to inflate their balloon so that its diameter is about 2 inches (5 cm) bigger. Have them again measure the distances from “MW” to each of the dots, and record
the distances under Time 2 on the worksheet. Have them inflate the balloon two more times in 2-inch (5-cm) increments. After each inflation, have them measure and record the
distances on the worksheet.
Once all the groups have collected their data, they can let the air out of their balloons. Ask students:
1. What did they notice about the distance from their Milky Way dot to the other galaxy dots as they inflated their balloons?
2. Did anyone have a galaxy dot that got closer to their Milky Way dot as the balloon inflated?
3. Which dots appeared to move the greatest distance—the ones that started close to the Milky Way, or the ones that started the farthest away?

2. Name: Group Name:
STUDENT MATERIALS
Page 1
BIG BANG BALLOON WORKSHEET
BIG HISTORY PROJECT / LESSON 2.3 ACTIVITY
Directions: In this activity, you’re going to work together with your group to better understand the balloon analogy for the expanding Universe.
Have someone in your group partially inflate your balloon until it is about 4 inches (10 cm) in diameter. Instead of tying it off, just have them hold the end tightly so that no air
escapes.
While one person holds the balloon without letting any air out, someone else in your group will use the felt-tip marker to make five dots on the balloon. Make sure the dots are
scattered all over the balloon. Label one dot “MW” and the other dots “A,” “B,” “C,” and “D.”.
Use the string and ruler to measure the distances from the “MW” dot to the other dots. Have someone in your group record these distances in the Time 1 column of your worksheet
table.
Now, inflate the balloon so that it is about 2 inches (5 centimeters) wider in circumference. Measure the distance again from your “MW” dot to the other four dots. Repeat this two
more times, inflating the balloon and measuring the distances from the Milky Way dot to the dots that represent other galaxies.
Working in your group, record the data you collect when you measure the distance between the “MW” dot and the other dots, for each of the four times you inflate the balloon.
Distance from the Milky Way Time 1 Time 2 Time 3 Time 4
A
B
C
D
Look at the data you collected with your group and answer the questions below. Be ready to share your answers with the class:
1. What did you notice about the distance from their Milky Way dot to the other galaxy dots as you inflated your balloons?
2. Did any of your galaxy dots get closer to your Milky Way dot as you inflated the balloon?
3. Which dots appeared to move the greatest distance—the ones that started close to the Milky Way, or the ones that started the farthest away?