Question: why is a flame going upward

Marta Maia answered on 13 Jul 2017:

When a candle burns, the flame heats the nearby air and starts to rise. As this warm air moves up, cooler air and oxygen rush in at the bottom of the flame to replace it. When that cooler air is heated, it too rises up and is replaced by cooler air at the base of the flame. This creates a continual cycle of upward moving air around the flame (a convection current), which gives the flame its elongated or teardrop shape. Because “up” and “down” are a function of the earth’s gravity, scientists wondered what a candle flame would look like in outer space, where the pull of gravity is minimal and there really isn’t an up or down. NASA scientists investigated how candle flames behaved in space, where there is no gravity. The a candle flame became spherical instead of its elongated shape on Earth. Without gravity, there’s no “up” direction for warm air to rise and create a convection current.