[hamdani yusuf]

https://en.wikipedia.org/wiki/Flame
The picture shows that there's no obvious correlation between colors in parts of flame and their temperature.

A flame test for sodium. Note that the yellow color in this gas flame does not arise from the black-body emission of soot particles (as the flame is clearly a blue premixed complete combustion flame) but instead comes from the spectral line emission of sodium atoms, specifically the very intense sodium D lines.

[Bored chemist]

By necessity, firefighters expanded the definition of fire even further.

Not really.
The definition of fire is simply stuff that's burning.
The fact that you can burn some metals doesn't alter that.

[hamdani yusuf]

By necessity, firefighters expanded the definition of fire even further.

Not really.
The definition of fire is simply stuff that's burning.
The fact that you can burn some metals doesn't alter that.

It's quite likely that, for hundreds or thousands of years, "fire" almost exclusively meant burning vegetation.
The interesting thing is that the definition has barely changed.

[Bored chemist]

In the days before they had worked out how to make magnesium, magnesium fires were unknown.
But if you showed someone  from that era some burning magnesium, they would have recognised it as fire because the definition is not dependent on the particular fuel.

[hamdani yusuf]

The video shows our current understanding on how fire occurs, especially in burning candles. The light is said to be produced by electrons falling back to lower energy orbitals after previously jump up to higher energy orbitals by absorbing energy. The problem is, the electrons in lower energy will absorb the light and jump to higher energy, which cancels out the light production by falling electrons, and leaving with the same light as the initial energy, analogous to Newton's craddle. But observations tell us that more fuel and oxygen mixture produce more light.

[Bored chemist]

The problem is, the electrons in lower energy will absorb the light and jump to higher energy, which cancels out the light production by falling electrons,

Since you can see the light from the candle, your "problem" is clearly imaginary.

Flames do absorb light.
https://en.wikipedia.org/wiki/Atomic_absorption_spectroscopy#Flame_atomizers
but not particularly strongly, so much of the light escapes.

[hamdani yusuf]

The problem is, the electrons in lower energy will absorb the light and jump to higher energy, which cancels out the light production by falling electrons,

Since you can see the light from the candle, your "problem" is clearly imaginary.

Flames do absorb light.
https://en.wikipedia.org/wiki/Atomic_absorption_spectroscopy#Flame_atomizers
but not particularly strongly, so much of the light escapes.

It means that the explanation in the video is incomplete. It's missing some important information in understanding how the light is produced. There must be some mechanism to get the electrons in the excited state other than absorbing visible light, which is not mentioned there.

Atomic absorption spectroscopy is based on absorption of light by free metallic ions.
https://en.wikipedia.org/wiki/Atomic_absorption_spectroscopy

I guess there won't be much metal in a candle flame.

[Bored chemist]

There must be some mechanism to get the electrons in the excited state other than absorbing visible light, which is not mentioned there.

Heat.

I guess there won't be much metal in a candle flame.

I doubt anyone ever thought there was.

[hamdani yusuf]

There must be some mechanism to get the electrons in the excited state other than absorbing visible light, which is not mentioned there.

Heat.

I guess there won't be much metal in a candle flame.

I doubt anyone ever thought there was.

How does an electron absorb heat? What happens to the heat source afterward?

Atomic absorption spectroscopy doesn't work on candle flame then.

[hamdani yusuf]

In this video I show you an amazing experiment where I actually make black fire! I show you how normally fire does not have a shadow since it is a source of light. Then I show you what happens when you shine a low pressure sodium vapor lamp on the fire. You still get no shadow, but something amazing happens when you put salt water on the fire! What how to make black fire!

[Bored chemist]

How does an electron absorb heat?

Hot molecules move quickly. When they hit eachother the electrons can get knocked into excited states.

What happens to the heat source afterward?

Nothing; why would it?

Atomic absorption spectroscopy doesn't work on candle flame then.

Yes it would.
AA doesn't only work with metals.

[hamdani yusuf]

Nothing; why would it?

Conservation of energy.

[Bored chemist]

Nothing; why would it?

Conservation of energy.

What do you think the "heat source" is?

[hamdani yusuf]

What do you think the "heat source" is?

Hot object.

[Bored chemist]

Well, it would get cooled, except that, since it's a flame, it stays at much the same temperature because it's heated by burning wax.