Tertiary Source

In a letter to Physics Today Roger Musson writes that the terms "Stone Age," "Iron Age," etc. refer to the material used most commonly to construct knives. This means we are currently in the Stainless Steel Age, possibly changing to the Plastic Age. By some reasonable measure, when would the transition happen?

Venoms have evolved independently in several different vertebrate lineages: in snakes and lizards, and in the platypus, and in one other mammal. What are the transitional stages for venom to appear? How would the appearance go in, say, a population of people?

How does the Stephan-Boltzmann constant σ "run" at temperatures where radiation modes other than photons become accessible?

A stopped clock is exactly right twice a day. With some error-weighted averages, a stopped clock is more accurate on average than a clock running, say, ten minutes fast. What averages do and don't have this property?

Supposedly volcanism on Io is caused (or enhanced) by tidal heating from Jupiter. What power does tidal heating dissipate in the Earth-Moon system?

What makes glassy smooth patches on the surface of a larger body of water? Why are the patches partially stable against rippling from outside?

How strong is the correlation between income tax witholding / refunding and tolerance for government spending?

What other neat tricks could you pull off using volunteer hardware as a distributed sensor network?

You can't interact with a physical system without disturbing it, though you can ignore the disturbance in the limit where ħ is small. Similarly, you can't interact with a market for some product (by asking or buying or offering or selling) without affecting the "market price" seen by others, but you can neglect that change unless your exchanges comprise a large fraction of the market. There is some correspondence here. Clearly it'd be easy to take this correspondence as justification for saying some really dumb things. Are there any useful insights there?

What's the pressure inside an unopened soda bottle (or can)? What's the rate at which CO₂ comes out of solution at ambient pressure? How much does the bubbling change the temperature of the liquid?