The hempcrete blocks make me think a whole lot of straw bricks, a pretty old composite technology - which falls into my frequently-reinforced observation that the more environmentally friendly a technology is, the more likely it is to be an updated version of technology that humans were using a thousand or more years ago.
Here the 'hempcrete' is really hemp hurd mixed with lime. The lime then absorbs carbon dioxide from the atmosphere as the hempcrete sets.
Hemp has long been put forth as a renewable resource with fibers that can be useful in lots of ways.
If you're interested in learning more about hempcrete...
This video definitely doesn't make me sad, though I would understand why you might end up a bit blue after learning about the manufacturing process of lapis lazuli-based paints.
The Cennini method described here is understandably expensive - because it's insanely labor-intensive.
Understandably, Mohammed has a less labor-intensive method that he developed, but he's not sharing that with us in the video.
From about 6:40 onward, the video shifts from following the production method to looking into the mining of lapis lazuli in Afghanistan, a more political discussion than the initial portion of the video. Then they come back to Mohammed as he explains why natural, lapis-based paints are 'better' than its synthetic replacements.
I was watching a YouTube video from a Scottish YouTuber recently and heard him refer to a light as being a LED bulb. He, however, pronounced LED as if it were the element lead. I, an American, pronounce those bulbs as their three separate letters El Ee Dee, like an acronym.
Neither, of course, is correct, nor is it at all relevant to this video.
This video, just over half an hour long and produced by Dr Derek of Veritasium, goes through the quantum mechanic explanation of how semiconductors conduct at room temperature which also explains how LEDs produce light and - eventually in the video - how LEDs can be tuned to produce different colors.
This video is also a great exploration of how doped semiconductors conduct electricity.
I'm really happy that I don't have to teach this concept in my chemistry - or material science - classes because this really pushes my understanding of quantum mechanics and electronics. I didn't thoroughly understand it when I first heard about it back in 1993 or 1994, and I don't entirely understand it now. I do, however, fully accept that there are people who do understand these concepts and that we owe those people a massive debt because the widespread use of LEDs has been a huge revolution in energy savings for our world.
I found the above video on Reddit (warning: NSFW word in the subreddit title) but with non-English narration.
I then found the embedded video in likely AI-generated English.
From there I found the Magnaseal website from Neothane which had the following two video embedded.
...and...
Sadly the Neothane website doesn't list any prices just a button to request a quote.
Other sitesselling the MagnaSeal, however, suggest that it's a rather pricey item, so I don't think I'll be picking one up to demonstrate in my classroom.
The iron presented is shown in weight of iron ore mined not of actual iron produced, and the rare earths are listed as "rare earth oxides", which I would also interpret as ore.
Some of the other metals seem to be presented in weight of actual metal produced (aluminum, for example, being listed as "smelted/refinery production").
Those quantities don't necessarily seem equivalent to me.
Today's video sees Grady looking at the NTSB's report on the collapse of the bridge.
The main issue can be mostly summarized as inspections that identified critical repair and maintenance on the bridge were ignored instead of being acted upon.
The report doesn't exactly fill me with reassurances that our infrastructure is safe for our daily use.
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.
