Analytical chemist water

Source: reddit

Water is water is water, right?

No, as I've posted here before, not all water is equal. 

The above video distinguished among four water types found in this particular analytical chemist's lab.

First is tap water. That's the stuff that is piped into our homes and businesses from the local municipality. Generally, in the United States, it's pretty clean and safe to drink. Depending on where you are, however, it could have various dissolved ions in it because of the pipes and rocks that the water passed through on its way to the water treatment facility and onward to your house.

Second is deionized (DI) water. To produce DI water, tap water is run across resin beads what allow for ion exchange. The positive ions in the tap water are absorbed by the beads and replaced in the water with hydrogen ions (H+) and the negative ions are replaced with hydroxide ions (OH-). Eventually those beads have to be recharged as their capacity to absorb ions is finite. 

DI water is not the same as distilled water, though both are 'cleaner' than tap water alone. I have used both distilled and DI water in college and summer camp chemistry labs. Both are certainly good enough for the chemistry work that we do on a high school level.

Third is MillQ water, produced by a three-stage process which is already light years beyond anything I've ever used in a lab. The video voice describes it as 18.2 megaohm[·cm] which measures the water's resistance to current. The more dissolved ions (electrolytes) water has, the lower its resistance.

Fourth, she mentions LCMS-grade water means Liquid Chromatograph/Mass Spectrometry water. I'm already out of my depths to explain why this water is purer than the previous water much less the final water she mentions - Optima LC/MS water.

However, as the comments on the video mention, all of this is problematic because of how the various waters are stored - dissolved silicium from glass bottles or CO2 or plasticizers if stored in polymer bottles.

How the World's Most Expensive Color is Made

This video definitely doesn't make me sad, though I would understand why you might end up a bit blue after learning about the manufacturing process of lapis lazuli-based paints.

The Cennini method described here is understandably expensive - because it's insanely labor-intensive.

Understandably, Mohammed has a less labor-intensive method that he developed, but he's not sharing that with us in the video.

From about 6:40 onward, the video shifts from following the production method to looking into the mining of lapis lazuli in Afghanistan, a more political discussion than the initial portion of the video. Then they come back to Mohammed as he explains why natural, lapis-based paints are 'better' than its synthetic replacements.

Units meme...

 Yeah, that's about right...I've said almost that exact phrase to my students probably a million times.

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.