[horo1988]

As I know from the bunsen burner study, blue flame is hotter than yellow flame.

I found there is one site says that blue flame happens when it receives a sufficient/right amount of oxygen.

I also found on the NASA website saying that blue flame is quite weaker than yellow flame in microgravity. Doesn't it mean blue flame is "colder" than yellow flame?

Please help me clarify all these confusions.

I 'm glad to hear from you guys.
(Note: my current conclusion is "yup, blue flame is hotter than yellow flame, but it is colder than yellow flame on Mir - can somebody tell me wat "Mir" means by the way? Isn't it a different place rather than Earth?

[Mitch]

Mir is a space station.

[horo1988]

Hello Mitch, so my current conclusion is right, isn't it?

[Renium]

If you carry a piece of sodium chloride into blue flame, it becomes yellow. Does it mean it becomes hotter or colder? I don't think so.

If you burn C2H2 in the air, you would get yellow flame. But if you burn it in pure oxygen, you would get blue flame, which is much hotter.

Sometimes blue flame is hotter than yellow, sometimes it isn't. It depends on the processes, which make the flame coloured.

P.S. There is more information about Mir:

http://en.wikipedia.org/wiki/Mir

[horo1988]

Very nice 

I see what u mean, but in the part you carry a piece of NaCl, the flame becomes yellow. Can you measure the temperature in degrees of that yellow flame to the temperature of normal blue flame? Are they equal? or the yellow would be lower degrees than blue?

My prediction is they are equal in temperature. The yellow flame is just the emission color from NaCl atoms.