For a time not so long ago a bunch of children around Bibra Lake were making "skylights" out of an ultral light black plasic bag and one of those Tea Light candles in the aluminium cup.
Mini hot air balloon and they did appear to move fast carried on the summer south West sea breeze at about 500 ft agl moving about at the whim of the wind.
Quite dangerous really as the candle was capable of burning for a long time, mass versus lift seemed to restrict them to about 500 ft depending on night air tempreature.
Some of them made it to YPPH.