Elkement’s Theory and Practice of Trying Everything has a charming post here inspired by the imagination-capturing question of what happens to a Slinky if you simply drop it (including a slow-motion video showing just how close reality can be to a Road Runner cartoon). She also puts forth an alternate explanation for just what is seen.

Slinkies are great physics (and mathematics) tools anyway, as they let you play for a while as you pretend to be working out how to model all kinds of wave motion problems.

elkemental Force

I have not known that this toy has a name at all. The ‘spring’ that can go down the stairs is called Slinky:

2006-02-04 Metal spiral

We all know how the Slinky walks – but how does it fall?

The following video might come as a surprise:

The authoritative article on The Falling Slinky is this one: Modelling a Falling Slinky by replacing it with a chain of masses connected by massless springs and calculating the trajectories of bottom, top and center of mass.

Edit: On replying to a comment, I searched for some written explanation by the professor featured in the video: And I found this great scientific paper an arxiv! The wave-like travelling of the “information that tension has collapsed” (as explained in the video) is put into equations.

I believe you could also explain it in the following way:

(1) If you are falling down you feel weightless –…

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