How to Make a Warning Last 10,000 Years

Alan Wiseman's The World Without Us has a chapter titled "Hot Legacy" that explores our efforts to create warnings that will last at least 10,000 years into the future and will tell future archeologists that the interesting stuff they've found at some of our nuclear waste repositories should not be explored.

Much of the research is being done at the Waste Isolation Pilot Project is New Mexico, USA, and it's that work that SciShow details in today's video.

I remember that the Wiseman chapter also mentioned the placement of various magnets around the site as a warning that something was at least weird in this location. The video doesn't mention that, and I'm surprised because I found that one of the more interesting ideas.

How Japanese Masters Turn Sand Into Swords

This isn't a replacement for the Nova episode "Secrets of the Samurai Sword". 

...but the Nova episode tends to appear and disappear from YouTube and DailyMotion with fair frequency, so you might need another video that goes through the ancient art of creating samurai swords from the initial collecting and smelting of iron-rich sand through to the slicing of tatami mats to demonstrate the sword's quality and the sword wielder's technique.

This video's contents...

• 2:00 - why bronze was used for sword and was eventually replaced
• 3:00 - cyanobacteria creating oxygen that precipitated iron from ancient oceans
• 6:30 - carbon + iron = steel, initial interstitial positions shown...why alloys are harder than pure metals
• 10:30 - slag formation and removal from the 'ancient' forge
• 13:30 - forging the steel by master swordsmiths
• 14:30 - folding the steel - how and why
• 16:15 - how carbon atoms migrate to different positions and form ferrite, cementite, perlite, and martensite
• 18:30 - differential cooling rates via clay thickness creating different steel types and the distinct blade shape

Another great video from Veritasium and one that shows that he's got a team of folks making videos with/for him at this point...and it's short enough at about half an hour - to get through in a single class period, unlike the Nova episode.

Why Are Chip Bags So Hard To Recycle? | World Wide Waste | Business Insider

Multilayer packages - MLP's - that's why.

It's not a tough answer at the most basic of levels. We've taken multiple materials - each of which accomplishes something useful for the overall chip package - and have fused them together in ways that make them nearly impossible to separate again and recycle.

Now, how are we trying to recycle them in spite of all the steps we've taken to make sure the materials couldn't easily separate?

Step one is to find a way to separate the un-separateable through heat, pressure, and high pH.

From there it's mostly down to regular recycling, but that first step is a doozy. 

This is the natural disaster to worry about

Forty-one minutes...that's the length of this video from Veritasium about the transformation of raw rubber into the amazing modern material we have today - primarily through the development of vulcanization by Charles Goodyear in the late 1800s.

In those forty-one minutes, Dr Derek explores - with seemingly a co-host for the first time that I've seen - the science behind rubber's stretchiness, the efforts to find an additive that can improve rubber's less useful properties, and a fungi that threatens the millions of rubber trees currently supplying our world's rubber needs.

But it's still forty-one minutes long...and that's without a whole lot of stretching.

Sorry...I'll see myself out.

Lamberts: Mouth blown Restoration glass - cylinder glass method - window

I've heard about and watched videos about the float method of producing flat, plate glass in which molten glass is poured onto a river of molten tin. The tin cools the glass very slowly and allows the glass to cool perfectly flat and smooth resulting in plate glass that can effectively be infinitely long.

I've also heard about crown or table glass (click here and scroll down a bit) in which an inflated ball of glass was cut open and spun into a flat disk. The larger the disk could be spun, the larger the panels of mostly flat glass that could be cut from that disk. The panels would by necessity be thicker on one side (the side nearer to the center of the disk) than on the other. 

Cylinder blown glass - as shown in the above video - requires a ball of glass with a bubble to be blown then swung into a longer and longer cylinder which is then cut open and laid flat to produce the flat pane of glass. The larger and longer the cylinder, the larger the pane of flat glass.

Float glass is much cheaper, but this cylinder glass process is far more fascinating to watch.

Molten Steel Exploding at 10,000fps - The Slow Mo Guys

There's not a ton of science in today's video, just some ridiculously slowed down footage of molten iron being smacked with a cricket bat by two British guys - thankfully with good personal protective equipment (PPE) for themselves. 

...but at least it's really, really pretty footage.

The $200 Million Mistake Hiding in Chicago’s Skyline

I need to remember to take my umbrella the next time I got to Chicago in case a 350-pound Carrara marble slab comes tumbling down from a building.

The building in question - now known as the Aon Center - was originally clad in the aforementioned Carrara marble, using panels that were 1.25 inches thick.

Apparently marble isn't terribly durable when going through extreme freeze-thaw-hot-summer cycles with each temperature shift leading to tiny cracks developing which allowed water to get into the cracks and freeze - like pot holes forming on the side of the (initially) world's 4th tallest building. 

Eventually, all the marble panels were replaced with granite which seems to weather the Chicago winters far better and is less prone to hurling itself off the building's facade and onto the tourists looking up with their mouths agape.