I appreciate that even though they won't give away their exact, secret recipe for their lead crystal that they do at least give us the basics of glass batching. It's the least that the French could do for us.
The video's mostly about the coolness of Saint-Louis glass blowers and carvers, but it's really cool to watch the glass being worked - especially the millefiori paperweights. Again, if you're looking for something to get your friendly, neighborhood blogger for Christmas...
It looks like the nearest Saint-Louis store to me is in Chicago...one more reason to get back to the Windy City.
I ranted last week about the lack of 5-10 minute YouTube videos, so I won't rehash that grumble pile this week.
Instead I'll mention that there's an urban myth (frequentlydisproven) that construction workers on the Hoover Dam either fell into an couldn't get out of or were purposefully dumped into the un-set concrete used to create the dam itself.
"No, they weren't," is the short answer. The long answer has to do with the inhumanity of such a practice, the long set time of concrete, and - as this video above shows - the high density of wet concrete.
Today's video sees Dr Derek in a wetsuit trying to fill a sphere with himself and a batch of wet concrete while cutting back and forth to various explanations as to the science of concrete, the most widely used material we have and the underlying backbone of our modern world.
And at about 9:30 we get the clear explanation as to why bodies were never sunken in concrete: bodies float in concrete.
Yes, the rest of the video is well done, explaining the history of concrete - primarily around the Roman discovery, the science of concrete setting, slump testing, ingredients in different concrete batches, clunkers, the environmental effects of concrete production, cement v concrete, and much more.
There's a whole lot to be said for YouTube videos that are five to ten minutes long. I can show an entire five to ten minutes in class without committing a full bell. The video likely has enough information to be useful but not so much as to be rambling around and further on a topic than I need to it.
But YouTube's algorithm seems to be killing those five- to ten-minute videos in favor of either long videos (between thirty and forty-five minutes from what I can tell of the posting patterns of my favorite YouTubers) and shorts that are less than a minute and a half.
I'm not happy about that.
...but I am thrilled about the video that I'm posting today and that is clearly too long to be shown in class on a whim. Today's nearly thirty-minute long video is a brilliant exploration of phase transitions of glass.
It starts with Destin recapping what Prince Rupert's drops (PRD) are, something he's covered in way more depth, then goes on to let Cal from Orbix hot glass - also from that earlier PRD video - try to capture a shattering PRD inside a class prison - rather than the epoxy prison that Destin tried to use previously.
Then at about 7:00 the stress-strain curve shows up, and we start to see that glass isn't quite as simple as we'd been lead to believe previously.
And a graph of viscosity versus temperature blows it all away around 8:00 where we hear that glass is a second order (more info here and here) transition material.
...and I was hooked. Destin continues to produce some of the best science content on YouTube.
That's 48 pounds of tungsten in a post office mailing box right there that people are trying to pick up.
Apparently it's really tough to pick up 48 pounds of tungsten - which makes sense because tungsten is really dense...but not as dense as osmium.
Apparently filling the same box with osmium would give you 61.5 pounds (source) - thankfully still below the post office's maximum weight limit of 70 pounds. To quote...
Osmium’s density is 22.6 grams per cubic centimeter. OP measured the inside dimensions of the small flat rate box and multiplied them to get the volume, 75.3 cubic inches. This is equal to 1,234.5 cubic centimeters. So all we have to do is multiply 22.6 x 1234.5. This gives us 27,899.7 grams, which is 61.5 pounds.
So, unless you go hunting neutron star matter or dark matter or something exotic like that, you're good to put just about anything inside one of those post office mailers.
