Pop-Pop Boats Are Weirder Than You Think

I've never heard of a Pop-Pop Boat before, so it's really not any weirder than I thought it was because I'd never thought of it at all.

Turns out the science of a pop-pop boat isn't all that different from the drinking bird. There's a contained amount of gas that is warmer than another amount of gas. That warmness causes the gas to expand and pushes liquid blocking that gas. In the case of the drinking bird, that unbalances the bird and makes it tip over. In the case of the pop-pop boat that liquid pushes the boat forward in a halting way.

Steve Mould's see-through model of the pop-pop boat doesn't, sadly, make the same pop-pop sound because there's no metal to snap back and forth, but it is a great way to see the inner workings of the boat.

Increasing intensity of chemical gradiant

See, it's funny because when you're following a smell, you're going from an area of low concentration of some chemical that your nose can register to an area of higher concentration. You're following a chemical gradient in the direction of increasing intensity.

Thanks, SMBC.

Why Rust Batteries May Be the Future of Energy - Iron Air Battery Technology

Rust! Un-rust! Rust! Un-rust!

Seems pretty simple...of course, the devil is in the details.

This video analyzes the possibility of an iron/air-based battery system for electricity storage, looking at where iron/air would be possible replacements as well as where they are not suitable replacements for lithium batteries.

What State of Matter is Fire?

No, water isn't wet. 

The is water wet? question suggests a misunderstanding of a word in chemistry. A single thing cannot be wet. A liquid will cover a surface better or worse than a different liquid. The better a liquid covers a surface, the better that liquid is at 'wetting' the surface.

It's like asking what your tongue tastes like. It doesn't taste. It tastes.

So, what state of matter is fire?

I like the analogy that Hank uses at 1:05 - what state of matter is a waterfall - works nicely for me. "A waterfall is a process caused by a bunch of liquid and gas and solids in a specific situation. ... A waterfall isn't matter because it's a process."

Fire then is also a process of fuel and oxygen reacting to form other chemicals (mostly carbon dioxide and water).

Fire is not matter, and Hank says that pretty well.

Electric Vehicles' Battery Problem

"To replace the UK (not the UK) 31.5 million gasoline cars will require 236,000 tons of lithium carbonate." ~ quote from about 1:00 in the above video.

That would - again, according to the video - require all the world's output for 9 months.

And that metal comes from some countries with awful human rights records and workers' protections.

Then, if we mine the US's lithium, we have to use up water and leach arsenic into the water supply of Nevada...and dig into land holy to Native Americans...and destroy habitat for endangered animals.

It's the frickin' Kobayashi Maru, man.

Then we have to look at the cobalt mining.

To quote a magnet I got from the University of Utah, "what's your is mined," but clearly what's mined is bad for the planet and people.

Geiger Counter

Source - XKCD
rollover text: At first I didn't get why they were warning me about all those birds sitting on the wire, but then I understood.

See it's funny because Geiger counters click when they detect radiation...and to say 'something clicked' also means that the speaker finally understood what was being said or observed. (source)

So the speaker could mean either that the Geiger counter clicked - suggesting that there was radiation around to be detected and justifying the presence of the Geiger counter itself - or that Cueball finally had his Eureka moment and understood why 'they' wanted him to carry a Geiger counter.

Either way, it's funny because it subverts expectations.

Decay chain of uranium-235

I came across this meme while scrolling back through @difluorine's twitter feed.

It's not @difluorine's work, but it's worth celebrating. 

To learn a little more about uranium-235's decay chain, check out this wikipedia article.