American scientists made a clocks ...
that goes forward a second if someone swears near it.
So for testing they put them in army barracks of England, France and Russia. After a while they go and check on clocks.
In England clock is 2 second forward. In France clock is 30 seconds forward. They now visit Russia and see that clock is missing.
They ask nearby solider :"What happened to the clock?".
Solider replies : "We didn't need that fan in here."