We Accidentally Discovered A RARE Scientific Phenomenon (10,000fps Collisions)

Most of this video - as is typical of videos from these ridiculous Aussies - can be skipped. It's primarily just repeated, slow motion footage of two giant air cannons firing random things (plastic dinosaurs, basketballs, cola cans, pumpkins, rubber band balls, spray paint cans, and such) at each other and ridiculous mugging for the camera.

But then - at 16:30 - they fire two glass balls at each other and something really interesting happens.

Well, at 16:30 they load the two glass balls and mug around for two and a half minutes before showing us the scientifically interesting slow motion video. Go ahead and skip to 19:00 to see the science.

I'll wait for you...

At 19:24 we get a flash of light when the two highly accelerated glass balls hit each other.

The flash of light certainly wasn't something that I expected to see and seems to be an example of triboluminescence (light produced from force or movement).

The initial science explanation (at 20:00 about IMFs being broken) seems a bit dodgy, and I'm really happy that they come back around 21:00 with something that sounds more correct to me.

I've never heard of glass causing triboluminescence (nor fractoluminescence which is a subset of triboluminescence, I guess), but I'd like to see somebody with way more science knowledge than I have explain what's happening here.

Thanks, by the way, to reddit for the gif.

Boxed cake vs scratch cake — Why bakers can't beat SCIENCE

A few years back - when we were still in the previous iteration of Princeton High School - I had my AP chemistry students make cupcakes with three separate leavening methods: baking soda, baking powder & soda, and mechanical leavening (whipping egg whites). The three methods are fascinatingly different and produce very different results.

In this video Adam and his baker friend look at the differences between box cake mix and from-scratch cakes. They're not quite looking at just the leavenings, but the science behind the differences are fascinating.

I'm sometimes sad that we went with material science rather than food science as one of our science electives at Princeton. I wish I had a good curriculum for high school students to explore food science, but that would also require a cooking classroom - something that our principal at the time of the building of new Princeton High School wasn't interested in building anything that practical.

Aluminum and mercury

I'm thinking that the dangers of mercury thermometers on aluminum-skinned airplanes has mostly passed us by - both because home mercury thermometers are all but outlawed and have been replaced by digital thermometers and because so little of a commercial airplane is being made out of aluminum at this point.

But the demonstration of the formation of mercury-aluminum amalgam is still really cool to watch.

Pee-riodic tables

The source of this image is a reddit post which included only the following explanation, "The bathroom in our science building has the periodic table in tiles".

I need more info. 

Where's the building? I assume it's a university science building, but there's no info provided.

Why do the metalloids seem to continue diagonally down from the table itself?

How old is the bathroom design? Nihonium (element 113) is the last element shown, and that was created in 2003 or 2004 with the discovery not adjudicated until 2015.

Why do the metalloids, halogens, and noble gases get to continue upward into the border design?

(Oh, and I can't take credit for the title joke. That came from the first comment on the reddit post.)

Modeling a Gas With Magnets

That works surprisingly well, though I'm terrified of magnets as large as Cody is using to vibrate the individual 'molecules'.

Floating stick man explained

I know, long-time blog followers have seen the floating stick man phenomenon before.

...but they haven't had Steve Mould explain why it works before, nor have they seen it used to animate an alien abduction.

How Do Dry Cleaners Clean Clothing

tl;dr - They use solvents with weaker IMFs that water - some of which are nonpolar.

It's been a big improvement over the ancient Roman 'dry scouring' which was based on fuller's earth, lye, and urine-sourced ammonia.

The solvents used have varied over time from turpentine, gasoline, benzene, and kerosene (all highly flammable, carcinogenic, and stinky leading most dry cleaning facilities to be located outside of densely populated cities) to tetrachlorethylene (which is less flammable but toxic to plants and animals and can lead to neurological issues like Parkinson's disease).

So, dry cleaning isn't remotely 'dry.' It's just cleaning with gentler machines using solvents that evaporate more quickly and readily than does water.

Liars...