Alright everyone, welcome back to Cody's Lab.
As you can see I'm putting some water inside of a steel vessel
into which I'm going to be adding an egg.
Now this isn't going to be particularly interesting,
until I add some frozen CO2, as you can see here.
This will increase the pressure inside the vessel, and
the CO2 will react with water, forming carbonic acid.
So let's go ahead and seal this up
And let her sit for a while, and see what it does to the egg.
Since I can't see inside the vessel, I also added some egg shells to a two-liter bottle
along with some dry ice.
This won't get to nearly as high a pressure
but at least I'll be able to see what's going on.
And, when the reaction is complete here, I'll know that it certainly is complete inside the vessel.
I'm actually recreating the natural process that forms limestone caves.
Rain water dissolves CO2 from the atmosphere,
forming carbonic acid
which dissolves the calcium carbonate.
Since egg shells are also made from calcium carbonate,
I should be able to dissolve them with the carbonic acid
In nature it takes a long time to dissolve calcium carbonate in rain water
In my Geology class, we figured that it was on the order of millimeters per century.
But I figured I could accelerate the rate significantly by increasing the pressure of CO2
and the concentration
You are currently watching 12 hours of the time lapse which I intended to make of this
Unfortunately, even accelerated a thousand times from what would happen in nature,
it was still way too long for me to time lapse
in fact it took 37 days to get the egg shells to this point here.
As you can see, the egg shells are dissolved
and all that's left is the collagen membrane.
So let's go ahead and have a look at the egg which I sealed inside of the pressure vessel.
Once I got it cracked open, I let it sit for a few hours to slowly depressurize
so the egg wouldn't immediately explode.
And it looked like that had worked!
...until...well, I'll let you guys see what happened.
"..didn't work out very well, did it?"
The liquids in the egg puffed up and exploded due to the CO2
coming out of solution.
The shell, however, remained relatively intact
and you can see that it's got significant karsting.
Compare it to this egg that hasn't gone through the same treatment
The shell is also much thinner as you can see from me just breaking it there
I think the reason why it didn't completely dissolve
is I just didn't have enough water.
And to be honest, the egg was probably pretty rotten anyway
after sitting for over a month.
But the egg shell pieces did completely dissolve
so let's go ahead and do something with these.
Let's start by filtering the calcium bicarbonate solution
to remove those collagen bits
and as you can see I've got
it on a pan,
which is sitting on the stove.
As I warm the water up, the CO2 is coming out of the solution
and calcium bicarbonate is only stable in acidic solutions containing dissolved CO2.
Which means as I drive off the CO2, the calcium bicarbonate
will turn back into calcium carbonate
which will precipitate from the solution.
And indeed it appears to have done just that.
After letting it cool and pouring off most of the water,
I went ahead and evaporated it dry
and as you can see I'm left with a very fine,
white powder of calcium carbonate.
This material closely resembles precipitate chalk
which is found in tropical regions
which makes sense because, again,
as the water warms up, it drops its load of carbonate.
Here is a diagram showing all the chemical reactions that happen here.
One thing I find is interesting is that the CO2 gas
is actually pulled out of the atmosphere
when carbonate is dissolving
and is released when carbonate is being precipitated.
I actually noticed that the pressure inside the bottle seemed to have dropped.
This is of course because the CO2 is being used up by the carbonation reactions
as the shells dissolved.
In nature, one of the major processes that removes CO2 from the atmosphere
is the weathering of rocks.
This means that if you have a mountain,
which is made of carbonate rocks, that gets uplifted,
the amount of CO2 in the atmosphere will drastically decrease.
And this may lead to lowering in global temperatures.
In fact, the Pleistocene Epoch started at about the same time as the Himalayas began up-lifting.
This means that Mount Everest may have actually caused the Ice Age.
Isn't that just amazing?
Anyway, I hope you all enjoyed,
and I'll see ya next time.