Mystery #3Tier 2weather / air pressure
How does an old-fashioned barometer hint that a storm is on its way?
In old houses you sometimes find a barometer on the wall, a dial you tap that points to 'fair' or 'stormy'. It has no radio, no screen, and no connection to anything. Yet it can warn you a storm is on its way. How does an old-fashioned barometer hint that a storm is coming?
Your guess
What's your hunch? How might an old barometer sense that a storm is coming?
There's no single magic word to type, have a go in your own words, then reveal the answer to see how close you got.
Make a guess to unlock the hints and the answer.