Flames in Space
The photo shows two flames, one on Earth and one in space.
On Earth, the heat produced by the candle expands the nearby gas, and it makes the gas more buoyant, so it rises and produces the tall flame. Up in the Space Shuttle, it's quite different, since the Shuttle, the air inside, and the candle are in free fall; everything falls around Earth together, so there is no up or down created by gravity. In space, the flame spreads out equally in all directions, distributing the heat into a far larger volume than on Earth, and producing the cool blue flame.
To learn more, visit Not Just Another Old Flame.
This feature was updated on July 2, 2013.
This web site, by astronomer Philip Plait, is devoted to airing out myths and common misconceptions in astronomy and related topics. There's a general section on misconceptions, and then examples from movies, the news, and TV. You'll find a bulletin board with a huge number of posts on a variety of topics.