All the chemical and quantum reactions that make a flame glow can only happen where it meets the air, so even though they look like solid cones, candle flames are actually hollow.

使火焰发光的反应都只能在接触到空气的地方进行，所以尽管蜡烛的火焰看起来像个实心的锥体，但它们其实是中空的。