June 20, 2019

WashU Expert: The global helium shortage hits home

Source - https://www.thoughtco.com/why-do-helium-balloons-deflate-4101553
It's been a decade or more since I first started hearing about a pending helium shortage.

But I didn't notice anything since then.

Sure, Party City posted something about the helium shortage, but I can't remember that last time I bought a helium balloon. I don't care about Party City being able to fill balloon orders or not.

We don't, admittedly have the most reliable helium 'production' system.
Three main sources produce some 75 percent of the world’s helium — sites in Qatar, Wyoming and Texas — > according to gas industry publication Gasworld. In fact the U.S. has for decades provided much of the world’s supply (from cnbc.com)
...and...
A versatile gas, helium is primarily used in electronics and semiconductor manufacturing and is particularly important for medical imaging, such as magnetic resonance imaging (MRI).

Helium is used as a cooling agent in MRIs and in manufacturing processes. Because helium is stable and does not react with other elements, it is also used in the making of semiconductors to create a contamination-free environment.

Still, the biggest consumer use of the gas is in party supplies — and that area is being hit especially hard by the shortage. (again, cnbc.com)

...

[A]nywhere between 50 and 200 of Party City’s 850 stores don’t have any helium in their tanks at any given time. (again, cnbc.com)
As I write this, Party City has announced the closing of 45 stores nationwide, including the one nearest Princeton High School, but we're going to be out a lot more than party balloons in the scientific realm unless we can either produce more helium (an unlikely outcome based on what I know about noble gases) or use it more efficiently.

Source - https://boingboing.net/2019/05/10/helium-shortage-deflating-part.html
As with so many things, I blame Cleveland.

June 13, 2019

World's Lightest Sold!



I've written about aerogel before (and perpetually mention the demise of my one piece).

But I haven't shown a video that uses a FLIR camera (1:00) to show the heat zones as they insulate a chocolate bunny from a bunsen burner using aerogel, where they show the industrial process of making aerogel (5:25), or especially where you actually get to see a supercritical fluid through the window (6:25 - the absolute highlight for a teacher who used to teach phase diagrams in AP chemistry), or where you get to see a mid-process 'wet' aerogel filled with alcohol (4:50).

If you happen to follow both of my blogs, you might see this double posted because of that supercritical fluid bit.

The above the line stuff is what I wrote over on my material science blog because those folks care more about material science. Here, though, we care more about the chemistry, so I'm going to focus on the idea of a supercritical fluid.

The basic definition of a supercritical fluid is, from Wikipedia, "any substance at a temperature and pressure above its critical point, where distinct liquid and gas phases do not exist. It can effuse through solids like a gas, and dissolve materials like a liquid."

See, the phase of a material depends on its pressure and temperature. We all know that water can exist as a liquid (between 0oC and 100oC at normal atmospheric pressure). Most folks know water can exist at even higher temperatures if it's under pressure (like in a pressure cooker). Below 0oC at normal atmospheric pressure, water turns into a solid, but if pressure is applied (like underneath the blade of a sharp ice skate) that solid turns into liquid without warming above 0oC.

If we graph all that, we get...

Source - http://wps.prenhall.com/wps/media/objects/4678/4791085/ch10_11.htm
In reality, water has a bunch of different solid crystal structures, so we could complicate things like this...

Source - http://ergodic.ugr.es/termo/lecciones/water1.html
...where each Roman numeral corresponds to one of the different, atypical crystal structures for ice. There isn't any real ice-nine, thankfully.

For carbon dioxide, as we see in the video up top, the phase diagram looks like this...

Source - same Wikipedia article for supercritical liquid as above
See that grey-blue area there, where it's not grey, and it's not blue but is rather a blend of them?

That's what we're seeing in the video.

And I've never seen it before.