"Richard Lamb" wrote

Then it turned around and floated back into the living room - and
rose back up to near 3 feet again!

While I understand the principles involved (temperature/pressure), I've
never seen such a clear demonstration of them.

Fascinating....

As kids, my brother and I would get a helium balloon, and make a gondola out
of a cut down paper cup. We would then add and subtract ballast, in the
form of tiny torn-up scraps of paper, to fine tune the hover. We could get
it to hover at about 5 feet, and it would follow the air currents around the
house. Tons (and hours) of fun!
--
Jim in NC