The Story of Stuff

This video is from 2009, so some of the details are admittedly a little dated, but the overall concepts - that we need to reduce our usage of materials in spite of the business community's desire for us to increase our usage and many governments' business-friendly leanings - are as relevant today as they were fifteen years ago (as I type this, anyway).

The channel has continued to make videos, posting their most recent (as of me typing this on July 4th, 2024) one in June of 2024, and they have a website with information on how to get involved in their campaign to decrease materials usage - particularly plastics and materials that end up in landfills.

Facets of Glass Physics

From online pdf

I'm going to have to give this article a couple more read-throughs to get all the content in it.

The article - from Physics Today's January, 2016 issue - goes into peer-reviewed detail of the thermodynamics of glass's formation, methods of forming glasses, a defining glass as a specific state of matter. I know the science would blow the heads off of our Princeton matsci students and would likely push my AP chemistry students to their very edges of understanding, but I learned a lot in reading the article and will go back through it a few more times to get a little more out of it.

The full article is available as a pdf as published or without the fancy title page.

Why on Earth is Depleted Uranium Used for Military Ammunition?

Depleted uranium just sounds terrifying. Sure, you can pick up some uranium ore and yellowcake from United Nuclear, but trying to buy depleted uranium is going to likely be a little dodgier.

With that being said, the US military has used depleted uranium (DU) as a source of armor penetrating ammunition over the years. I thought - wrongly from the video above - that the DU was simply used because of its high density and nature otherwise as nuclear waste. Today's video posits that there are quite a few other advantages of DU in high-caliber munitions applications.

There are also some seemingly obvious health risks involved in living in an area where spent DU shells are peppering the ground or having been in a tank where DU rounds entered and as least slightly vaporized. The video also goes through those health risks and says that they have largely been disproven, though I would be skeptical and appreciate that many military branches are "not considering depleted uranium anymore because of the environmental problems associated with it, be [they] real or perceived."

I think I'll stick to good ol' tungsten for my armor piercing needs.

A glass that builds and heals itself

That looks a whole lot like solgels to me, but I'll admit that my knowledge of solgel chemistry is about twenty five years out of date and based on a single summer of research at Miami University (no, not University of Miami).

The video summarizes researchers' findings that amino acids can form glasses with an index of refraction close to that of silica glass, adhesive properties, and a natural inclination to form convex lens shapes...and that self heal themselves as they rehydrate themselves.