Download BIG BANG BALLOONS

BIG BANG BALLOON
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:
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1 round latex balloon
Sharpie marker
60-cm piece of string
metric ruler
Procedure:
1. Write the title and purpose of this lab in your Journal.
2. Copy the data table from the board into your Journal. (Use a ruler!)
3. First period students, cut a piece of string 60 cm long. (After that, reuse the same pieces of string!)
4. Inflate your balloon until it is about 10 cm in diameter, but do not tie the end.
5. Using the Sharpie, make six dots on the balloon in widely scattered locations. Label one dot "home"
and the others A, B, C, D, and E. The home dot represents the Milky Way galaxy, and the others
represent galaxies formed in the early universe.
6. Without letting air out of the balloon, use the string and ruler 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!*
7. Inflate the balloon so that its diameter is now about 15 cm.
8. Again measure the distances to each of the dots, and record them under "Time 2."
9. Inflate the balloon in 5-cm increments three more times. After each inflation, measure and record
the distances in your data table.
10. In your Journal, answer the discussion questions in complete sentences in such a way that
someone could understand your answers without reading the questions.
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.
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. How did
you figure this out?
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.
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.
2. 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. How did
you figure this out?
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.