We describe a set of conceptual and hands-on activities based around understanding the dynamics of a Slinky that is hung vertically and released from rest. This Slinky drop experiment typically lasts a fraction of a second, but when observed in slow motion, one sees the Slinky compress from the top down while the bottom portion remains at rest—naively seeming to defy gravity—until the Slinky has completed its collapse. The motion, or lack thereof, of the bottom of the Slinky after the top is released sparks student curiosity by challenging expectations and provides motivation and context for learning about scientific model building.
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The bottom of the Slinky does not remain completely at rest, but it actually twists before the collapse completes. The torsional wave associated with this phenomenon moves much faster than the longitudinal wave and was explored as a final project by one group of students. https://www.youtube.com/watch?v=fbUmv5ok-so.
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One group of students explored the connection of this experiment to the concept of the center of mass as a “balance point” for their final project. https://www.youtube.com/watch?v=5I2NCp4MDXU.
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Exploring different choices in the implementation of the numerical simulation was the subject of one of the final projects. https://www.youtube.com/watch?v=OWy3lzXDcmY.
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This comparison was done qualitatively during instruction, but a quantitative comparison was the subject of a final project. https://www.youtube.com/watch?v=s0eIhpMeKZU.
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