Can you light a match with water?

My first teaching job was at Terre Haute South Vigo High School in Terre Haute, Indiana.

At THS (we pretty much just called it Terre Haute South), one of the other science teachers gave me a coiled copper tube that looks pretty much like what's shown in the video and was used for exactly what it's used for in the video.

I think I set the demonstration up once...maybe twice ever...and had that copper tube in my storage drawers at three separate schools. I can't remember offhand whether I brought it over to the new building. I think I'll check, though.

But, that's not what the video is about. The video shows how water can be heated to vapor which can then be superheated to a high enough temperature to set a match aflame.

The video also goes on to explain why the copper corrodes so thoroughly.

Kind of cool neat.

An Actually Good Explanation of Moles

This video is brilliant, and the title is surprisingly accurate.

I've been defining a mole for two and a half decades now, and I've never quite approached it from this angle. The mole is simply a quantity that relates the mass of different elements that react together.

I like that.

The rare property of pumpkin seed oil - dichromatism

(Warning: almost dirty word at 1:35)

Is pumpkin seed oil something that any of you have around your house?

I think we have vegetable oil, olive oil, peanut oil, baby oil, motor oil, and safflower oil. I'm pretty sure we don't have pumpkin seed oil.

In this video, Steve Mould breaks down how we see color (three cone cells in your eyes) and how translucent liquids show the colors that they show...especially how pumpkin seed oil shows two totally different colors depending on how deep the puddle of liquid is.

I wonder if there are any artistic uses for pumpkin seed oil.

(By the by, you can see a more accurate version of the pumpkin seed oil spectrum on wikipedia.)

Why all solar panels are secretly LEDs (and all LEDs are secretly solar panels)

In the fall of 1995, Professor Arthur B Ellis of UWisconsin came to Wabash College - where I was then a senior chemistry major - and gave a presentation about LEDs. At the time I knew of LEDs as the little red or green light bulbs that were pretty much used as power indicators on electronic devices. I didn't - before his talk - have much of an idea how they worked or how important they would come to be in our world now twenty-five years later.

Coincidentally, Dr Ellis had just written Teaching General Chemistry: a materials science companion, a book that my cooperating teacher bought for me after my student teaching semester later that academic year and that I accidentally re-purchased twenty years or so later. (I realize now that I've told this story on the blog before.)

But I digress...I have come to realize that Dr Ellis's lecture at Wabash really laid out the chemistry of LEDs marvelously well because I watched the above video - showing the LEDs and solar panels are of a kind - and the below video - in which Steve Mould explains the science of LEDs and how they turn electricity into light (and the reverse in solar panels) - and realized that I already knew that information...even down to the P- and N-type semiconductor information.

I've never had a chance to thank Dr Ellis for his lecture, so maybe - if I'm lucky - he'll come across one of these blog posts and realize that he's appreciated.

Hiding a Nobel Prize From the Nazis

So much chemistry here.

Great explanation of a famous story of Neil Bohr's lab - particularly George de Hevesy - dissolving two gold Nobel prize medals to hide them from the Nazis...and then precipitating the gold back out of solution a decade or so later once the Nazis had been defeated.

It's a great story, and the science - full d-shells, equilibrium, Le Chatelier's principle - is outstanding. The story itself is better told in this NPR post from Same Kean's The Disappearing Spoon book, but Kean doesn't go into the science as well as Hank Green does here.