Materials:
Analyze and Conclude
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Petri Dish
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Red marbles represent protons.
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Blue marbles represent neutrons.
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Pom poms represent electrons
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Procedure:
1. What atom was modeled above? How do you know?
2. Explain how the mass changed when the electrons were
added.
1. Place an empty petri dish on the scale and press zero/tare.
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2. Add six red marbles to the petri dish. Record the mass in
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the Data and Observations section.
3. With the red marbles still on the balance, add six blue
marbles to the petri dish. Record the new mass in the
Data and Observations section.
4. To the balance, add six pom poms (electrons). Record the
new mass in the Data and Observations section.
Data and Observations
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3. Based on this lab, what can you conclude about the mass of
protons, neutrons, and electrons?
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4. Why were pom poms chosen to represent electrons?
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5. What are some limitations of this model?
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Question:
How can you model the mass of an atom?
An atom is mostly empty space. However, the protons,
neutrons, and electrons that make up the atom do have mass.
How does the mass of an atom’s electrons compare to that
of the protons and neutrons in the nucleus?
Pre-lab Questions:
1. What does the prefix sub mean? _______________
2. What are the three subatomic particles?
a. _____________________________
b. _____________________________
c. _____________________________
3. Why do you think they are called subatomic?
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