Phase Change Materials. wmv

I remember the Cincinnati Bengal mascot coming to our school a decade or so ago, back when Becky and I were running the Pasta for Pennies campaign (and raising $30K-40K in a month doncha know). He was there for what we called the Wacky Olympics, a celebratory picnic and bunch of games that we held at the end of our fundraising year. We would have grade-level (and staff) teams compete in stupid games (pass the orange, four-legged race, stuff like that), eat hot dogs, drink punch, and generally have a blast.

One year the local Leukemia and Lymphoma Society chapter arranged for the Bengal mascot to come out and celebrate with our students. It happened to be a nice, 85-degree day, though, so I was a little worried that our mascot would end up with heatstroke. He explained to me that he had 'ice packs' that weren't really ice under his costume. Those packs were filled with a material that undergoes a phase change from solid to liquid at around 70^oF, meaning that they'll have a stable temperature at that range for a long time, keeping the mascot-suit-wearing human close to that temperature for a long time.

The video up top shows a material similar to that being used in wall materials to keep the office at a fairly stable 23^oC (73.4^oF).

The videos below show something a little more like what the mascot wore under his costume.







How cool is that?

Colourful Chemistry: Chemistry of UNIVERSAL INDICATOR

Source - James Kennedy

Back in the day, we didn't get a whole lot of science educational content on television. It was pretty much just Mr Wizard, and by the time I was watching him, he was in reruns on Nickelodeon.



If you haven't seen Mr Wizard, you should check it out before watching Sam Rockwell's science skit on Saturday Night Live.



There certainly are days when that feels all too familiar. Thankfully, I don't drop the language that Sam Rockwell did.

But I digress...

In that first video up there, Mr Wizard explains to his young assistant how you can check the pH of a solution using an indicator solution of red cabbage juice. I've done the red cabbage experiment, and it's a blast. The cabbage contains anthocyanins that change color depending on the pH.

In the chemistry lab, though, we rarely use red cabbage juice. Yes, some science suppliers will sell it, but most would much rather sell a solution of universal indicator, made up of a solution of four indicators that produce a lovely and in-order rainbow of colors as the pH increases.

Thanks, by the way, to James Kennedy for putting the top-most infographic together.

Super Expensive Metals - Periodic Table of Videos

Are they really worried that The Professor is going to rob the place that they had to strip him and even take away his belt?

Rhodium, iridium, palladium, and platinum are impressively un-reactive, noble metals.

In the video today we get to see these catalytically useful metals being processed from sponge (what I would think of as ore).

I love seeing what I think of as a crude process like forging being used to reshape the incredibly expensive ingots.

And I doubt these are the absolutely most expensive metals out there - I'd put the sodium from previous videos up there - but it is a chance to answer a question I get from students from time to time: "what is the most expensive element?"

Corrosion in Motion Golden Gate Bridge

I just love the special effects from the first half minute of the video. The tentacles, in particular, are hilarious.

The explanation (1:25) of a single piece of iron having both anodes and cathodes due to random electron movement, however, is actually really good. I wish they'd go into more depth there.

Don't Play With ACID SLIME

Why would you ever think that making acid slime was a smart thing?

Making a video and project based on a moronic YouTube comment seems like a really bad idea, not necessarily anything especially dangerous, just something dumb.

The acid clearly doesn't let the slime 'set up' which isn't really all that surprising because polyvinyl alcohol slime holds together via cross linking (check the graphics here), and the extra hydrogen ions would likely break down all of those cross links - if not even depolymerize the PVA.

The pH test strips, by the way, are absolutely useless there because all of the acids that they're testing would have pHs well below 1, leaving them likely outside the useful range of the strips.

That was dumb.

Crystal Birth

Crystal Birth from Emanuele Fornasier on Vimeo.

That's just pretty...and relaxing to watch.

Here we get a bunch of chemical reactions producing metal atoms from metal ions. Some are single replacement reactions. Some are - I think - electrical reduction (I'm assuming that because there are gas bubbles appearing in some of the reactions).

For the most part, we get very little information as to what reactions are taking place, with the only text in the video saying things like Bi⁺³ --> Bi but not mentioning any anions being involved.

Either way, this is definitely reduction happening as every reaction changes a metallic ion into the metallic atom that then forms the crystal.

Stick around for the lead crystals at the end (from about 2:23 onward). They're gorgeous.

And not lead crystal...lead crystals.

Flying squirrels secretly glow pink, thanks to fluorescence

I remember visiting the Grand Canyon a few years back and getting a post-sunset tour from the park ranger. He took a ultraviolet flashlight and looked around at the desert around us. It took him maybe ten seconds to find a scorpion fluorescing in the blacklight.



I spent the rest of the hiking trip sleeping on the picnic tables.

I haven't been shown the fluorescent, flying squirrels, but I'm thinking I wouldn't be nearly as scared of them as I was of the scorpions.

Read more about this at NatGeo or Smithsonian.