I found a lighter one day and lit it and thought to myself, "why do flames have the shape they do?" I hypothesized maybe it was similar to water-the surface tension that allows one to lay a needle across the water. However, what I found was actually quite interesting.
The picture attached shows what a flame looks like when gravity is present (left) and when it is not present (right).
Buoyancy- a concept I wish to become more familiar with in the future- is a result from gravity. Why does the flame become the shape of a teardrop? These are the reasons I found:
The products from the combustion that creates the flame go out due to buoyancy while oxygen is drawn in towards the flame.
Solid particles are convected upward to create the yellow tip of the flame.
Finally, to overcome heat loss, the flame migrates in towards the wick.
Whereas if we compare the flame where gravity is absent, the flame creates a spherical shape because there is no "up" or "down". There is also a lack of oxygen which leads to lack of "soot" to be convected upward and a lower temperature. The loss of temperature also results in the flame to migrate away from the wick.
I thought this was actually pretty neat! I really want to learn more about flames and specifically buoyancy as well.