Karen Lise Krabbe: Gelled Glass

That's absolutely fascinating.

I've seen the reverse spherification technique of using sodium alginate and calcium chloride solutions to produce edible, gelled products (Kool Aid worms, gelled drink spheres, cocktail pods). Sometimes the calcium chloride is swapped out for calcium lactate because it's really the calcium ions that are necessary for the process.

But using that process to make gelled glass which can be shaped in ways that glass normally couldn't be shaped is pretty amazing. All respect to Karen Lise Krabbe for developing this technique. If you want to learn more, you can check out her ebook on the technique.

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

The materials in our world are rarely pure. Our steels are alloys. Our polymers contain dyes and plasticizers. And apparently our food packaging - like chip bags - are composed of nearly a dozen different polymer and aluminum foil layers glued together.

Trying to get those materials apart again to recycle them is currently all but impossible to recycle.

If only those layers could be separated again...

Uses of expandable foam

Found on reddit...

We were talking about the expandable, polyurethane foam in class after doing the lab, and I wanted to hunt down some uses of the foams outside the classroom. I figured if I'm looking for them, some of you might be interested in them, too.

If you have any other good videos of uses of expandable foam, please link to them in the comments.

More after the jump...

What's 'activator' or 'magical liquid'?

Most years, I give my students some freedom after the AP chemistry exam. There's still so much more chemistry to learn, but I've completed the required curriculum for the year, so we can explore a few cul de sacs of chemistry.

We've played Minecraft because they told me there was a bunch of actual chemistry involved - which turned out to be kind of true. There's certainly a whole bunch of material science involved.

I've also had them research chemistry programs as universities around the midwest, practice and perform a demonstration for my non-AP course, and honestly - write a blog post for my chemistry blog. 

Today's post, however, is about the time my students asked if they could just make slime. We make polyvinyl alcohol slime in first year chemistry, but they wanted to make glue (which I recognize is often PVA-based) slime. One of the students said she had a gallon of Elmer's school glue at home from her Covid lockdown slime days (apparently slime-making was a thing for many school-age students during Covid lockdown?)

In discussing what they could bring in, other students in the class offered to provide shaving cream (apparently to make 'cloud' slime - a fluffy variation), small fruit-shaped slime charms, glitter, and non-staining food coloring. I, generous sort that I am, offered my leftover borax solution from the crystal making experiment early in our matsci curriculum. It's a little more than the 4% concentration called for in most slime recipes, but it's close enough.

One of the students asked me if the borax solution took the place of the activator. I'd never heard of an 'activator' solution before, so I started looking around online.

Apparently the borax solution + PVA/glue solution with which I am most familiar has some alternatives - sort of. There's the 'borax-free' variety using baking soda and contact solution, but the contact solution has to contain boric acid - which would be neutralized into...um...sodium borate (aka borax) with the addition of sodium bicarbonate (baking soda). There's also the option to just purchase pre-mixed activators, one of which - shown in the image - is Elmer's Magical Liquid.

With a quick check of the Magical Liquid's SDS, I see that it's a solution of boric acid, sodium bicarbonate, sodium chloride (?), and a couple of anti-microbial agents. The various concentrations seem lower than I would have thought: <1% boric acid, 1-5% sodium bicarbonate, <1% sodium chloride, and <0.5% of each of the preservatives. I'm feeling too lazy to do the math to do actual calculations, but I'm pretty sure the combined percentages - discounting the bicarbonate and the chloride masses - would come out decently below the 4% of the borax solution I'm used. Wonder if that's just a case of commerce allowing for the lower concentration leading to more needing to be purchased.

At $17 per quart (from Amazon as of 6/7/26 when I'm typing this up), the magical liquid has to be a high margin item for Elmer's. It's more expensive if you want your slime to be green-apple-scented. Sadly the cherry limeade scent looks to be sold out and might be out of production now - even though Elmer's still has it listed on their website.

Cherry limeade's my favorite...grape's favorite, too.

This Genius Magnet Stops Dangerous Leaks in Seconds!

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 sites selling 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.

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.

Checkerspot x Autodesk: A Better Future for Snow Sports (and more)

In the summer of 2023, our field trip from the Salt Lake City ASM summer teacher camp was to WNDR / Checkerspot.

When the trip was initially described to me, I thought we were going to see how snowboards and skis are made. I'm not a winter sport guy, so I figured it could be interesting but not necessarily my scene.

When we got there, though, I found that WNDR - the winter sports equipment maker and retailer - wasn't the real business. The real business was Checkerspot, a materials company that was producing polymer raw materials from microalgae as a replacement for petroleum sourcing. 

That company needed some way to demonstrate the utility of their materials, so they found a consumer-focused industry with high margins and a strong environmental conscience among its consumers. In the Salt Lake City area, skiing and snowboarding made sense for them because the final products - the snowboards and skis themselves - are high users of polymers in their composite materials, and the people who buy tend to be willing to spend a little more to buy environmentally friendly products.

The tour was outstanding, and I highly recommend getting to see their process if you're ever out in Salt Lake City. You can see some of their facility in this next video.

Making ULTRA-BRIGHT GLOWING GOO

Barnaby Dixon is an impressive puppeteer that I first heard about probably ten years ago. If you haven't checked out some of his work, do yourself a favor and spend a few minutes there first.

In this instructional video, Barnaby explains how he uses a thermoplastic polymer - a polymer that becomes flexible when it's heated above some temperature but is rigid below that same temperature. It's a great example of the polymer's glass transition phase change. Because polymers are mixtures, they don't necessarily have definite melting temperatures as pure substances like elements or compounds do. Instead they have ranges of temperatures during which they aren't quite solid or liquid but are flexible and moldable - think of hot glass being shapeable but not liquid.

I have some of this at school. It used to be available from Educational Innovations. That's where I bought it, but they sadly don't carry it anymore. Of course, just about anything is available at Amazon if you search for pcl moldeable plastic.

How One Company Secretly Poisoned the Planet

At some point in my material science and chemistry courses, I speak bluntly to my students that most research suggests that man-made polymers are bad for us.

Some are worse than others, but most research on the effects of polymers on humans seems to suggest that there are bad effects from most man-made polymers. Some are minorly bad, but others - like the family of PFAS - are more obviously and persistently bad.

The video above is short and has a direct message: DuPont is bad (or has acted badly).

The longer video below - from Veritasium - is far longer but is much, much more informative.

If this sounds familiar, you might've seen a semi-recent movie about this story, Dark Waters.

How Disc Golf Discs Are Made (MVP Manufacturing Tour) - Smarter Every Day 301

Summer of George!

I do want Destin to get back to making shorter videos like his initial, six-and-a-half-minute Prince Rupert's drops video, but I understand that he's just working to optimize for the algorithm. 

At least the Smarter Every Day videos are quality videos from tip to tail, showing brilliant views and asking questions along the way of the entire manufacturing process.

I learn so much from all of Destin's videos.

And I'm going to get myself some of those MVP discs. 

The worry about black plastic...and a correction

This video was published by Adam Ragusea in November 2024 about a study from a month or so earlier than that. 

The tl;dr of the study is that many black plastics are produced from recycled black plastics that are frequently sourced from electronic waste which contains higher amounts of particularly toxic, flame-retardant chemicals. Those 'new' black plastic items could - especially if used in high heat areas like food flippers and turners on the stovetop - release higher than safe amounts of those chemicals.

In the above video, Adam goes through the possible concerns that this raises as well as noting a possible math error in the study's calculations suggesting that the level of concern is slightly lower than the authors might have initially suggested.

The article was corrected - noting exactly the math error that Adam suggested, and Adam published a spectacular video explaining why that error should not undermine faith in the scientific process or even in the researchers and authors of the original article.

You're Being Lied To About Ocean Plastic | Truth Complex | Business Insider

The widening gyre...

Yes, there's a garbage patch in the center-ish of the Pacific Ocean. 

That garbage patch is not anything worth looking at, though. It's an area of higher than average concentration of plastic waste, but it's not something you could walk across or would have trouble boating through. Even a higher density area isn't necessarily a high density area.

As this video reveals, the most common photos attributed as being of the garbage patch are not of the garbage patch. They're of near-shore, highly polluted areas - which might actually be easier to clean up than the garbage patch would be - if we even should clean it up.

The video goes on to explore the sources of plastic pollution (hint - mostly not littering), the value of recycling (limited but worth doing), the role of big corporations in producing plastic waster (suck it, Coca Cola), the problems with microplastics (bad, very bad), and the need to reduce more than reuse and recycle.

These kinds of videos are way too easy to find on YouTube.

Plastics bad...we need to use less of them.

...and I write that as I sit beside of plastic bottle of Coke Zero Cherry that I'm drinking today.

Can this sugar-based material replace single-use plastics? | All Science. No Fiction.

Sugar glass itself isn't the solution to single use plastics.

It's too brittle and too water soluble.

But it sounds like the composite of sugar glass (isomalt) and sawdust - particularly with a waterproof coating - might be a promising possibility.

Indestructible books

A month or so ago, my wife brought home an Indestructibles book. She'd picked it up from our local Target store as a baby shower gift for a coworker and said it was made of a neat material that didn't rip.

I asked if it was Tyvek, knowing that Tyvek is a rip-stop fabric. She, a successful Appalachian Trail thru-hiker knows Tyvek as a lightweight ground cloth, and she said she wasn't sure whether the books were Tyvek or not.

So off I went on an internet hunt...

On the Indesctructibles FAQ page, I found the following... 

What are Indestructibles made of that is so durable yet paperlike and delightful for my baby?  

Indestructibles are printed on a synthetic material made from flashspun high-density polyethylene fibers (getting technical here, we know). It feels like paper, but liquid water cannot pass through it and it is very difficult to tear.

Which then sent me to the wikipedia article on flashspun fabrics...

Flashspun fabric is a nonwoven fabric formed from fine fibrillation of a film by the rapid evaporation of solvent and subsequent bonding during extrusion. 

...and wikipedia links onward to 'see also' Tyvek...

Tyvek (/ˈtaɪ.vɛk/) is a brand of synthetic flashspun high-density polyethylene fibers. The name Tyvek is a registered trademark of the American multinational chemical company DuPont, which discovered and commercialized Tyvek in the late 1950s and early 1960s. 

 

Tyvek's properties—such as being difficult to tear but easily cut, and waterproof against liquids while allowing water vapor to penetrate—have led to it being used in a variety of applications.

See the parallels between the Tyvek entry on wikipedia and the Indestructibles description?

waterproof...liquid water cannot pass through it...

difficult to tear but easily cut...very difficult to tear...

flashspun high-density polyethylene fibers...flashspun high-density polyethylene fibers

The books might not be made from the branded Tyvek, but it sounds to me like they're made of a generic Tyvek.

I'm going to take that as a win.

The Controversy Behind Nike’s Vaporfly Running Shoe, Explained | WSJ

Anything more than totally naked sporting competition is essentially a materials question.

Wooden tennis racquets gave way (briefly) to aluminum and then to composite racquets.

Wooden baseball bats became aluminum then composites.

Similar progressions took place for pole vaulting and nearly every other sport.

In running, however, the materials question mostly shows up in the running shoes, and Nike's Vaporfly is the current materials leader in that realm.

More videos after the jump...

Meet The Plastic-Eating Worms | Planet Fix | BBC Earth Science

I am both hopeful about and horrified at the prospect of enzymes that will break down plastics.

I'm hopeful because the man-made polymers that we have been creating and covering our world with for decades now are going to have to be broken down somehow, sometime. If decomposers are beginning to be able to process them into harmless - or even beneficial - products, that's great.

...but we have a lot of currently in-use polymers that we don't necessarily want to start breaking down into gray goo just yet.

...and if we find a way to make polymers break down more easily, will that just encourage us to make more of those polymers rather than stopping the production of them sooner?

Like Natalie Imbruglia, I am torn.

The life and achievements of chemist Stephanie Kwolek, inventor of Kevlar

Stephanie Kwolek absolutely belongs in the inventors hall of fame, in the women's hall of fame, on the American Chemical Society's website, and on lots of other lists of honorees.

Stephanie Kwolek, you see, invented Kevlar at DuPont in 1965.

Why Melted Bugs On Candy And Lemons Fuel A $167 Million Industry | Big Business | Business Insider

The process of making shellac is scientifically fascinating, ridiculously complicated, economically important, and ethically questionable.

Like so many products that are 'natural', shellac amazes me because I have absolutely no idea how anyone would have thought to go through this process to turn bug secretions into a furniture sealant, a citrus fruit polish, a candy coating, and so much more.

Self-Healing Material

Self-healing materials could be pretty cool if we get them figured out.

I appreciate the brief dalliance into cold welding between metallic pieces in space - something I've posted about before.

And I appreciate Steve Mould, of course, who sadly keeps his humour (British, natch) mostly in check for this video.