Big Bang Balloons

BIG BANG BALLOONS

Introduction: In the 1920s, astronomer Edwin Hubble realized that light coming from galaxies is shifted into the longer, red wavelengths. This would indicate that they are moving away from Earth. By carefully observing the light from galaxies at different distances from Earth, he determined that the farther something was from Earth, the faster it seemed to be moving away. This relationship has become known as Hubble's Law.

Hubble’s discovery helped lead to the current theory of the origin of the universe. In this lab, you will make a model of what Hubble observed and use it to draw conclusions about the nature of the universe.

Purpose: to model the expansion of the universe

Materials (per group):

 1 round latex balloon  Sharpie marker or ballpoint pen  measuring tape  ruler

Procedure:

1. Write the title, date, and purpose of this lab in your Journal.

2. Tape or glue the data table neatly into your Journal right after the purpose.

3. Inflate your balloon until it is about 10 cm in diameter, but do NOT tie the end. (Just pinch it!)

4. Using the Sharpie or pen, make six dots on the balloon in widely scattered locations. Label one dot "home" and the others A-E. The home dot represents the Milky Way galaxy, and the others represent galaxies formed in the early universe. 5. Without letting air out of the balloon, use the measuring tape to measure the distance from home to each dot. Record the distances in the data table under the heading "Time 1." (Remember! Data tables should be filled in with a pencil!)

6. Inflate the balloon so that its diameter is now about 15 cm.

7. Again measure the distances to each of the dots, and record the distances under "Time 2."

8. Inflate the balloon in 5-cm increments three more times. After each inflation, measure and record the distances in your data table. 9. In your Journal, answer the discussion questions in complete sentences in such a way that someone could understand your answers without reading the questions. The Discussion questions should come AFTER the data table! Big Bang Balloon Data Table:

Distance Time 1 Time 2 Time 3 Time 4 Time 5 from Home(cm)

Big Bang Balloon: Discussion Questions

Directions: Write the answers to these questions in your notebook in complete sentences in such a way that someone who did not know the question would understand your answer. Make sure to CITE ACTUAL DATA in your answers to support them!!

1. How did the distance from the home dot to each of the other dots change as you inflated the balloon?

2. Do the dots nearer home or farther away from home appear to move the greatest distance?

3. Based on your answer to #2, determine if the closer or farther dots are moving faster. Explain the evidence that you used to make your inference.

4. Now imagine that the home dot is our own Milky Way Galaxy and the rest of the dots are other galaxies. In 1920, astronomer Edwin Hubble observed that galaxies behave the way the dots on your balloon did as it was gradually inflated. In other words, they are moving away from our own galaxy and each other. He also determined that the farther away a galaxy is, the faster it appears to be moving away from us. What could Hubble conclude about the universe from this evidence?

5. Your model was a pretty good one, but not a perfect one. Unlike the two-dimensional surface of the balloon, the universe has three dimensions. Describe a good model for a 3-D expanding universe.