January 28, 2019

GIANT Liquid Nitrogen Rockets: Explodes In My Face



The title's a bit of an oversell.

Yeah, I know, you're shocked that a youtube video would use a clickbait title.

The bottle does, however, explode just above the host's head. That happens for a couple of reasons, primarily that the bottle he used for that part of the experiment is made for holding change not for holding pressurized gases and liquids. The polymer involved is more rigid, weaker, and assembled in two parts rather than as a single shell.

All that being said, I'm really happy with the safety precautions that the host takes. He's wearing gloves to protect against the cold and a face shield to protect his face and eyes. I do wish he had some earplugs in because the explosion can be loud, but he did at least take decent precautions.

Don't do this, folks...but do watch this.

January 21, 2019

25 Chemistry Experiments in 15 Minutes | Andrew Szydlo | TEDxNewcastle



Dude, you didn't put your goggles on for like a minute or two into your demonstrations.

That's going to be 10 points from Ravenpuff....or Huffleclaw...or Slytherdoor...whichever...

In all honesty, however, I'm kind of impressed with this guy's constant stream of chatter through the entirety of his presentation. Even when he finds himself pressed for time, he doesn't let the patter slow even a little bit.

He does seem a bit frazzled, though, but I do like all the experiments that he shows - other than the liquid nitrogen in bottles. That seems unsafe to me.

January 14, 2019

How Is Black Fire Made?



TL;DW - it involves sacrificing a virginal chemistry student to the chemistry gods...

jk

Actually, this one's pretty brilliant. It's the distinction between emission and absorption spectra.

See, when the yellow light is produced (or emitted) - as shown around 1:00 in the video - it's because electrons are bouncing up and down within the atom (as shown via a Bohr model). That's an emission spectrum.

That requires energy. In the fire that energy comes from the chemical reaction of the ethanol (remember kids, no methanol) with oxygen...burning.

When the sodium vapor light is on, however, it's providing exactly the right amount of energy to excite those electrons. Which is then absorbed by the sodium atoms in the flame, leaving behind no light at all. That's an absorption spectrum.

And that's so cool...

January 7, 2019

Why I changed my mind about nuclear power | Michael Shellenberger | TEDxBerlin



I'm shocked...

Like stunned...

I grew up in a firmly anti-nuke, Gerry Brown kinda household. My mom swears I didn't eat a grape until I was like five years old because she wasn't going to support the farmers against the migrant workers. There was always Bob Dylan playing on the record players, and nukes were nothing but death in waiting.

And nukes meant both nuclear weapons and nuclear power.

I remember visiting Marble Hill - a never-operational nuclear power plant in Southern Indiana - either during high school or college, and it freaked me out because nuclear power - which very nearly came to that power plant just an hour from my home - was a practical demon in a bottle. I'm pretty sure that my mom was one of the folks protesting against Marble Hill's construction in the early 1980s.

But it looks like my mom just might've been wrong.

The video shown above presents pretty strong evidence that nuclear power might be the better alternative to solar or wind power.

I'm going to have to do some more research.

And the video below - also from Michael Shellenberger, who appears to have a decent number of bona fides - tells the story of how nuclear power shifted from being an environmentalist's darling to being everybody's boogeyman.


January 6, 2019

Just for my students

I'll give 5 EC points to the first current student of mine to send me an email saying that they saw this message.