Hand Sanitizer Fires Are Invisible

Yeah, I guess hand sanitizer - mostly ethanol - fires are pretty hard to see, but I'm really glad that Steve Mould here goes into the dangers of methanol for the second part of his video.

If I haven't mentioned methanol to you yet, you should check out all of my methanol videos.

Piezoelectricity - why hitting crystals makes electricity

Piezoelectricity is so cool.

The fact that if you deform crystals, you can produce a voltage difference to get a spark...or that you can introduce a voltage difference to deform a crystal (like how a fan is a generator but in reverse or how LEDs are solar cells but in reverse) is amazing to me.

And Steve Mould's explanation of why that works - with the crunchy and smooth peanut butter lids - is just brilliant.

I'd known that piezo crystals were the guts of a grill lighter for a long time, but it was a long time before I found out other uses like the 'speakers' within greeting cards or microphones and guitar pickups.

The Curious Case of the Xenon Balloon - Periodic Table of Videos

There's an AP chemistry problem that I vaguely remember. The problem showed four balloons, each with initially identical volumes, temperatures, and pressures. The balloons were filled with helium, oxygen, nitrogen, and xenon gases respectively. (This is entirely from memory, but the details aren't 100% relevant to where I'm going with this.)

The questions underneath the prompt and diagram then asked something about which... 

• particles had the greatest average kinetic energy (they're the same because temp is proportional to average kinetic energy)
• particles had the fastest moving particles (helium because Graham's Law of Effusion says that the smallest particles - if all are at identical temperatures - move the fastest to make up for the lower mass)
• balloon had the greatest mass (xenon because they're at the same temp, pressure, and volume, so they have the same number of moles and xenon has the greatest molar mass)
• balloon would be expected to be the smallest after a day

It's that last one that's relevant to this video.

In the answer I remember, the helium balloon would be the smallest because its particles are the least massive, so they're moving the fastest at the same temperature. That means they'll randomly hit the microscopic holes in the balloon (all latex balloons have tiny holes we can't see with our naked eyes - imagine a rubber band ball inflated), so the helium would get out of the balloon the fastest (it would effuse through the tiny holes) leaving the helium balloon the smallest after some amount of time.

But it seems like xenon might be the correct answer for a much more complicated intermolecular force reason.

Vlad, I think I owe you a point retroactively.

Chemistry is dangerous.

If you're not aware, NileRed - Nigel Braun - posts some really fascinating chemistry videos over on YouTube. 

I'm tempted to blog pretty much everything that he posts because the reactions are brilliant and often are things that I wouldn't remotely feel confident in doing myself. He's a chemist, and I'm clearly a chemistry teacher - very different training and levels of confidence with chemicals.

Recently, on his alternate channel NileBlue, Nigel posted a great video about the safety precautions that he takes in all of his work. The above video is long - twenty-four minutes long - but covers a great breadth of safety concerns from what clothing to wear to how to minimize risks by never working alone.

If ever you're tempted to do any chemistry at home - Nolan, I'm looking at you - you should watch this entire video and buy yourself a lab coat and some high quality goggles.