The physics behind this is pretty obvious, of course- the warm air rises, but if the surrounding air is too warm, that is where the issue lies.
Does anyone know what a "perfect" outside air temperature for Sky Lanterns would be?
There is also the issue that if the air is very cold, then the fuel cell won't be able to heat the air in the ballon to a sufficient temperature for it to rise.
Finally, just wondering, what is an average price for these? Around the £3 mark sounds about right, typically discounted if bought in bulk. I have noticed, too, that quality CAN vary a bit.
This is also worth reading, about a British alternative- UFO Balloons
Edited by David, 05 July 2009 - 04:31 PM.