# Category Archives: Physics puzzles

## Puzzle: A Cube Of Resistors, Updated With Links To Solutions

I posted this puzzle a few days ago: Consider 12 identical resistors connected to form a cube. That is, each resistor lies on the edge of a cube, and there is an electrical connection joining three resistors at each of … Continue reading

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## Puzzle: A Cube Of Resistors

Here’s a puzzle I just read in Clifford Stoll‘s book High Tech Heretic (paraphrased by me): Consider 12 identical resistors connected to form a cube. That is, each resistor lies on the edge of a cube, and there is an … Continue reading

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## Why Does A Propane Torch Get Cold When Used? Updated, With Refrigerators

I was fixing a leaky water pipe in my garage yesterday, and so I had occasion to use a propane torch to heat up the pipe and melt the solder into the joint. It’s not something I do often, but … Continue reading

## When a metal ring is heated, does the hole expand, contract, or stay the same size?

Spoiler alert: The puzzle is answered in the update at the end of this post. Most solids expand when heated and contract when cooled. Water/ice is anomalous in that it expands when cooled, at least near its freezing point. If … Continue reading