Black Hole Lab
Problem Statement: How does a star’s volume, mass, and density change when it turns into a black hole?
IV: Volume of star
DV: density of star
Mass stays the same
Hypothesis: If the star’s volume decreases then the density will increase.
Materials:
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Aluminum foil
1 balloon
Measuring tool
Needle
Scale
Calculator
Procedure:
1. Blow up the balloon until it is fully expanded (Make sure not to pop the balloon). Tie off the end, and
cover the balloon with the sheets of aluminum foil. This will be your “Model Star.”
2. Measure the circumference of the aluminum foil star. In your data table, record this value as Trial 1
Circumference.
3. Place the Model Star on the scale. Record the mass (grams) under Trial 1 Mass.
4. Now Supernova! Poke a hole in your balloon by puncturing it with a needle. Gently shape the
aluminum foil back into a “sphere”. Measure the circumference of the now collapsed Model Star.
Record the value as Trial 2 Circumference.
5. Obtain the mass of the collapsed Model Star and record the value as Trial 2 Mass.
6. Squeeze the collapse star a little more. Measure the circumference and record your data as Trial 3.
7. Repeat the mass measurement and record your value appropriately.
8. Squeeze the collapse star so that you make it as small as you possibly can. Repeat the circumference
and mass measurements and record that data. For each circumference, calculate the radius of the
sphere. Remember, this is done by dividing the circumference by 2π (π = 3.14) . Record the results
appropriately in your data table.
9. Now calculate the volume [(4/3) πr3] of the sphere for each radius.
10. Calculate the density for each trial.
11. Data:
Data
Trial
Circumference
Radius
Volume
Mass
Density =
1
2
3
4
Conclusion:
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Explain what you did in the experiment.
What did the balloon represent before you popped it?
o After you popped it?
What happened to the volume of your Model Star from trial 1 to trial 4?
Did the mass change from trial 1 to trial 4?
o Why or why not?
What happened to the density of your Model Star from trial 1 to trial 4?
Restate your hypothesis.
o Was your hypothesis correct or incorrect?
o Provide evidence (Data (numbers), observations)
Answer the problem statement.
Evaluation:
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How confident are you with your data?
o Why?
What are some sources of error? (What are some things that sent wrong during your lab?)
How did you fix these errors? (or avoid them the next time this lab is performed)
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