Puzzles

This is a collection of puzzles, mostly about physics, that yield to simple, insightful solutions. I have tried to avoid any that require calculus. Some of these are classics with a history that goes back to the 19th century or earlier. Some I invented myself.

Some have answers, but not all answer discussions are complete. Puzzles with asterisks are essentially finished. Those without links are in development, or not yet written. Those with dates have appeared in the SPS Obeserver.

Leonardo wheel puzzle. A perpetual motion wheel?
Bessler's belt puzzle. An overbalanced belt perpetual motion device.
Windup chain puzzle. An overbalanced belt perpetual motion device.
The eccentric wheel puzzle. A failed perpetual motion device.
Testing Bhaskara's wheel. Testing perpetual motion wheels.
Touchy equilibrium. A balanced wheel.
The tilted hemisphere. Plane and simple, one moving part.
The slippery soup bowl. A slippery slope.
The rod and bowl. Slippery equilibrium.
The sliding slot puzzle. A challenging equilibrium puzzle.
Swinging physics. Fall 2015*
Sound Reasons. Winter 2015*
Compass confusion. Spring 2016*
Loopy physics. Summer 2016*
The resistor tesseract. Taking it to a higher dimension.
Archimedes' hat box. A classic problem in geometry.
Cannonball collision. Fall 2016*
Pendulum perplexity. Correcting the "Big Ben" clock. The curious mouse. Winter 2016*
Chasing rainbows. First version. Spring 2017*
Chasing rainbows. Second version. Spring 2017*
Forensic physics puzzle. Moon inside rainbow.
The button spinner. A physics toy.
Pressure paradox.
Buoyant Optimism. *
Finding equilibrium.
Reflections on rainbows. Where is that pot of gold?
The soda can. *
Fried Earth. *
Two-Lamp Problem. Switching series/parallel.*
Flat plate pendulum.
The whirlygig. *
Weighing an Atwood Machine. Needs serious revision.
Freshman physics revisited. *
Numerology. *
The skater's spiral. *
Fingering the center of graviy. *
Roberval's balance.
Mixtures.
Heavy finger.
Leonardo's ornithopter.
Dick and Jane walk the dog.
Dick and Jane measure refractive index.
Mirror reversal.
Challenging Physics Puzzles.
Physics Problems to Challenge Understanding, emphasizing concepts and insight.
82 more physics puzzles!