Via the always wonderful What if? what may be my new favourite silly paper. Longuet-Higgins M. S., Math. Proc. Cambridge. Philos. Soc. 50 (2) p347 (1954) “On Slinky: The Dynamics of a Loose, Heavy Spring”

I can’t help but think there are some fun A-level/undergrad experiments to be had out of that. Come to think of it, I have a staircase, so if I get a slinky…