Summary

In this demonstration, students use a hula hoop that has a ball in the center (hung from a string) to simulate Rutherford’s gold foil experiment.

Grade Level

High School

NGSS Alignment

This demonstration will help prepare your students to meet the performance expectations in the following standards:

• HS-PS1-3: Plan and conduct an investigation to gather evidence to compare the structure of substances at the bulk scale to infer the strength of electrical forces between particles.
• Scientific and Engineering Practices:
  • Developing and Using Models
  • Analyzing and Interpreting Data

Objectives

By the end of this demonstration, students should be able to

• Demonstrate Rutherford’s Gold Foil Experiment using a modified hula hoop and a ball.
• Show how Rutherford’s Gold Foil Experiment shows that most of an atom is empty space.
• Show how Rutherford’s Gold Foil Experiment shows that there is a dense nucleus in the center of the atom.
• Visually represent what we learned from Rutherford’s Gold Foil Experiment.

Chemistry Topics

This demonstration supports students’ understanding of

• Atomic Theory
• Atomic Structure
• Model of the Atom
• Rutherford’s Gold Foil Experiment
• Subatomic Particles

Time

Teacher Preparation: 5 minutes

Lesson: 5-10 minutes (can vary depending on teacher preference)

Materials

• Hula Hoop
• 2 Tennis balls (or something similar)
• String
• Tape

Safety

• Students should wear proper safety gear during chemistry demonstrations.

Teacher Notes

• In advance of the demonstration the teacher must tie a string around the ball and attach it to the hula hoop so that it hangs in the middle. Tape will help secure the string on the hula hoop and on the ball.
• I introduce this lesson by discussing the evolution of the atomic theory the day prior.
• I also use this AACT video resource that discusses the contribution of important chemists to the atomic model, from “The Founders of Chemistry” video series.
• I usually use this demonstration as an opener for the day. I start the lesson by asking what two main things that Rutherford’s Gold Foil Experiment taught us. Then as the kids are discussing answers, I bring out the hula hoop and the extra ball.
• Next, I choose a student to throw the ball from across the room and try to hit the ball in the center. Very rarely do they hit it.
• I usually have the same student try multiple times (~10) to show how unlikely it is to actually hit the center. Also, to add the “random” factor, you could blindfold the student who is throwing the ball, since Rutherford was not “trying” to hit the nucleus.
• I use this phenomena to emphasize that the Gold Foil experiment taught us two main ideas: The atom is mostly empty space and there is a dense nucleus in the center which sometimes (but not often) deflects the ball (just like in Rutherford’s experiment). Here I also reference how small the nucleus really is. I use the analogy of a grain of rice on the football field from our textbook to drive that home. With this in mind, you could also use a smaller object in the center of the hula hoop, like a small bouncy ball or marble to really emphasize the size disparity.
• This demo is engaging and is often referred back to as we continue our discussion of the atomic theory and the structure of the atom.
• I don’t have students record anything during the demonstration, but you could have the students draw how the see an atom in their head after the demonstration. This could be useful to make sure that you drive home the main points and will also give you an opportunity to dispel any misconceptions that are still lingering. You could also have them come up with their own analogy with regards to either size or empty space to compare an atom to. Getting the students to relate the atom to something they experience daily is very beneficial since it is so hard to give them hands on experience with the actual nucleus of an atom.