When the balloon was in the skywill the air inside the balloon cool down if the flame was turned off?

Yes, if the flame is turned off, the air inside the balloon will eventually cool down. As the balloon rises, the surrounding air temperature typically decreases, and without the heat source from the flame, the warmer air inside the balloon will lose heat to the cooler external environment. Over time, this will cause the air inside the balloon to cool, potentially leading to a decrease in buoyancy and causing the balloon to descend.