Why It Was Almost Impossible to Make the Blue LED

I was watching a YouTube video from a Scottish YouTuber recently and heard him refer to a light as being a LED bulb. He, however, pronounced LED as if it were the element lead. I, an American, pronounce those bulbs as their three separate letters El Ee Dee, like an acronym. 

Neither, of course, is correct, nor is it at all relevant to this video.

This video, just over half an hour long and produced by Dr Derek of Veritasium, goes through the quantum mechanic explanation of how semiconductors conduct at room temperature which also explains how LEDs produce light and - eventually in the video - how LEDs can be tuned to produce different colors.

This video is also a great exploration of how doped semiconductors conduct electricity. 

I'm really happy that I don't have to teach this concept in my chemistry - or material science - classes because this really pushes my understanding of quantum mechanics and electronics. I didn't thoroughly understand it when I first heard about it back in 1993 or 1994, and I don't entirely understand it now. I do, however, fully accept that there are people who do understand these concepts and that we owe those people a massive debt because the widespread use of LEDs has been a huge revolution in energy savings for our world.

Plus it lets people wrap their cars in Christmas lights.

Why Airport Security Suddenly Got Better

I'm far from a frequent flier, typically taking one or two round trips a year for our summer camps - and I'll admit to a fair skepticism of the security theater that we have at airport, but...

I find the science that we're using at airports kind of fascinating.

In the future, though, I'll be aiming for the dual-energy CT scanners that this video covers. 

The video - once the three-minute intro about travel wraps up - explains how X-rays are absorbed by various materials of various thicknesses. 

Oh, warning the Brian does say, "pain in the a**" at about 9:59.

Tattoo Removal Is Insane

I can't imagine what sort of tattoo I would've gotten when I was 20 or so.

U2? Queen? Wabash College? University of Aberdeen? Lambda Chi Alpha?

No matter what I would have chosen, I'm pretty sure it's not something I would have wanted to be an identifying feature on my body now thirty years further down the line.

So I'd've had to invest time, money, and some pain to get that tattoo removed.

Today's video goes through the science and process of getting tattoos removed.

Tl;dr - it doesn't sound fun.

The Hidden Danger Inside Every Candle

This is this third time I've posted a video about this demonstration, one I still haven't done in my own classroom.

I don't know that the action lab does a better job explaining things, but he certainly does a better job filming the flaming cloud from up close.

The Penicillin Myth

That video above isn't the real thing I'm posting today, and this isn't really a chemistry post at all. It's a general scientific method post.

That video tells the popularly-understood and oft retold story of how Alexander Fleming discovered penicillin in 1929.

The actual link I'm sharing today - from Asimov Press - is titled "The Penicillin Myth" looks at Fleming's story of the discovery and posits "maybe he didn't."

See, the article details some flaws in the discovery story - namely that a plate initially inoculated with staphylococci and subsequently contaminated with penicillium would not actually kill the staph bacteria since penicillin only affects growing - not mature - colonies.

In the article, Kevin Blake recounts two other theories of how Fleming might have actually discovered the effectiveness of penicillin with slight differences from Fleming's story.

The article is a great exploration of the scientific method - of the importance of record keeping, the ability of other scientists to replicate experiments, and what effect historical inaccuracies in how a discovery was made have on the importance of the discovery itself.

How to Make a Warning Last 10,000 Years

Alan Wiseman's The World Without Us has a chapter titled "Hot Legacy" that explores our efforts to create warnings that will last at least 10,000 years into the future and will tell future archeologists that the interesting stuff they've found at some of our nuclear waste repositories should not be explored.

Much of the research is being done at the Waste Isolation Pilot Project is New Mexico, USA, and it's that work that SciShow details in today's video.

I remember that the Wiseman chapter also mentioned the placement of various magnets around the site as a warning that something was at least weird in this location. The video doesn't mention that, and I'm surprised because I found that one of the more interesting ideas.

These Rings Absorb Light and Glow in the Dark

I've found something new that I want to own...

These would be a great demonstration for when we're talking about electron transitions in chemistry class. I do wish, however, that I knew what the glow powder chemistry was so I could at least talk about the various colors and which compounds were making which colors.

For now, though, check out the ring manufacturer's website where the rings are selling for $59 (with a black Friday discount as I'm typing this)