While scrolling through social media you might have seen some pictures of bright blue lava flows
and raised a skeptical eyebrow
And hey! Good for you doubting stuff on the internet because photoshop is a thing
But those photos are real
Even though the molten rock isn't what's blue, it's actually combusting gases
that make the glowing blue flame
A volcanic crater on the island of Java in Indonesia called Kawah Ijen
is the best place to see this phenomenon at night
Plus, the crater also has a deadly vivid turquoise lake which is full of acid
The chemistry of the volcano causes both of these briliant colors but in two different ways
Lots of volcanoes spit up gaseous sulfur compounds
Like the Dallol Volcano in Ethiopia
So blue flames aren't unique to this crater
But Kawah Ijen happens to have spectacular amounts of sulfur,
enough to support a huge mine
The miners are after the bright yellow chunks of solidified sulfur rock
But its sulfur forms a yellow solid,
why do the sulfuric gases seeping up from the ground burn blue?
It all has to do with the chemistry of combustion
When a fuel like a sulfur compound mixes with oxygen and high enough temperatures,
a combustion reaction happens
Heat gets released and new chemicals are formed like sulfur dioxide
and the visible part of the fire is the flames
which are caused by a bunch of atoms spewing out light energy
Basically the energy from the combustion reaction
boosts the electrons in the fuel atoms to a more energetic state
When the electrons fall back to their original state,
they release all that extra energy as a photon of light
The wavelenghts of those photons determine what the flame's color is
And in the case of sulfur compounds catching fire, it's an eerie blue glow
During the day, Kawah Ijen's lava looks pretty much like the orangey-red lava of any active volcano
Although the sulfuric gases are still burning, but the bright sunlight washes the color out
But at night, sightseers flock to see all of the glowing blue flames on the rivers of molten rock
If that wasn't enough to make Kawah Ijen one of the world's weirdest places,
then there's also that turquoise acid lake
Volcanoes tend to bring all sorts of chemicals from the Earth's interior up to the surface
And in Kawah Ijen's case, there are plenty of things besides sulfur
like chlorine and a bunch of metal
In the crater lake water, the sulfur dioxide gas made by the combustion reaction
dissolves and forms sulfuric acid
And the chlorine compounds mean that there's hydrochloric acid in there too
The pH of that crater lake is no joke below 0.5
which is really really acidic, like stronger than the acid in your car battery
Needless to say don't go swimming in that death lake no matter how cool it looks
Even just measuring the pH of the water can be a really dangerous job
Acid that strong can dissolve metals no problem
And dissolved metals do something that
organic carbon containing chemicals usually don't, they turn bright colors
The color you get and whether you get a color it all has to do with the chemistry
and geometry of the metal ions floating inside the solution
Many kinds of metal ions absorb certain wavelenghts of visible light
And your eyes perceive color based on the wavelenghts of light
that are reflected off an object
So, when a metal ion absorbs one color of visible light,
you'll usually see a complementary color to the one that's absorbed
The hue that's across from it on the color wheel
If a compound absorbs light outside of the visible spectrum,
all of the visible light gets reflected and the solution looks white or clear
That's why organic chemistry might as well be called
six hundred colorless compounds and how to draw them
In organic chemistry is where all the colors are
So, the mixture of dissolved metals in Kawah Ijen's lake
is what makes the water look vividly turquoise
If the volcano were to erupt, there's a chance that the lakebed could rupture
and send that acidic "death water" cascading down the mountain to do serious harm
And because Java is so densely populated,
volcanologists keep a very very close eye on any volcanic activity in the area
So Kawah Ijen owes its incredible colors to sulfur compounds
Whether they're burning or dissolved in the lake with some metals
Those two different kinds of chemistry make this weird place
a beautiful and deadly destination
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