Oddly, I had heard that old battleship steel - from before the development of atomic/nuclear weapons - was highly valuable for non-radioactive shielding material.
This video does a great job explaining how the Trinity explosion - and subsequent open-air, atmospheric testing of nuclear weapons - polluted any steel made after those tests via the Bessemer process for producing steel from pig iron and using atmospheric air.
I did not know, however, that the battleships scuttled at Scapa Flow had subsequently been salvaged and some of the steel used in this way. (As an aside, your friendly, neighborhood blogger has visited Scapa Flow. It's gorgeous.)
And I also didn't know that the demand for this low-background steel has mostly been superseded because of the switch from Bessemer to basic oxygen steel production.
I'm talking about the first half of the above video, during which Chris Rowlatt shows us how he produces marbled papers for eventual book binding. The marbling involves putting a nonpolar ink (or maybe dye, I'm not sure the technical distinction there) onto polar water. The two materials don't mix, so the nonpolar ink can be lifted from the surface of the water with paper.
I can't remember where I first saw this density bottle. It might've been from Educational Innovations at one of our ASM summer camps...or maybe from Flinn Scientific at one of their NSTA workshops.
Either way, I have one of those bottles in my classroom, and nearly every student who plays with it love and is fascinated by it.
There's so much goin on with the bottle (the full video of which you can watchin real time at 4:30).
There's solubility concepts - salt water and isopropyl alcohol being immiscible.
There's polarity concepts - food coloring being differently attracted to the two liquids (I recommend green food coloring not the red that Mould uses here. Just add green food coloring and see what happens.)
There's density concepts - the five substances in the bottle (air, isopropyl alcohol, salt water, white/translucent beads, blue beads) line themselves up by density.
There's polymer concepts - the two beads are made of different polymers (the company wouldn't tell me what polymers, and I've asked). The blue beads are sold as pony beads. The top beads - at least the ones in my bottle from Ed Inn - are sold as UV-detecting beads.
There's electromagnetic wave concepts - turns out that the less dense beads are UV beads. I'd had the bottle for years without knowing that because my classroom at the time had no windows, so I hadn't noticed that. Now that I know it, though, it's pretty cool.
There's IMF concepts - the bottle is shrinking a bit as liquid evaporates even through the bottle over the course of years. That's stunning to me, but I swear that I haven't opened the bottle even once in those years. Something must be going on.
But, see the mantis (murder) shrimp moves its...um...pedipalps, I think...so fast that they create cavitation bubbles which end up stunning its prey before the killing strike.
Didn't you watch PhysicaGirl's previous video about all that?
You should check it out.
I love that much of the video here is about fact checking a viral video - because the science we get from many of those videos is a whole bunch of bunk.
The science in this video mostly isn't about the bottle at all but rather about cavitation, a fascinating phenomenon that has all sorts of ramifications - like with corrosion, for example, or biology.
I love the slow-mo video of the bottle smacks - even down to the shockwave and soniluminescence.
