At some point in my material science and chemistry courses, I speak bluntly to my students that most research suggests that man-made polymers are bad for us.
Some are worse than others, but most research on the effects of polymers on humans seems to suggest that there are bad effects from most man-made polymers. Some are minorly bad, but others - like the family of PFAS - are more obviously and persistently bad.
The video above is short and has a direct message: DuPont is bad (or has acted badly).
The longer video below - from Veritasium - is far longer but is much, much more informative.
If this sounds familiar, you might've seen a semi-recent movie about this story, Dark Waters.
Uranium glass (not actually on the list but mentioned in the introdution)
Dentures - The uranium added to the porcelain in the 1940s helped the 'teeth' look more natural - including absorbing ultraviolet radiation like natural teeth do.
Toys - I recognize that chemistry sets from the mid-20thcentury weren't remotely safe, but the current 'chemistry sets' might have swung a bit too far the other way.
War - Not just atomic bombs here but also depleted uranium used in tank shielding and armor-piercing rounds. I've posted about this use before.
Medicine - I hadn't heard about this use of uranium to treat diabetes before, but it sounds like it wasn't useful and was even harmful. Might want to check that whole Hippocratic thing.
Spas - Tom Scott had a video on these spas - which sound like really bad ideas to me.
I understand that the act of creating fire at this point in our lives is trivial.
I have a couple of piezoelectric grill lighters and a flint-based lighter in the a drawer in my kitchen. The 'pilot lights' in my gas stove, hot water heater, and furnace are all piezoelectric. If I need fire, I can have it in about two seconds.
That hasn't always been the case, of course. From prehistoric times when fire meant warmth and digestible food, the act of fire creation was miraculous and to be protected.
So the development of a 'safe' lighter that could create fire at the whims of the lighter's owner was an important step toward taming that fire.
But I certainly wouldn't want to carry around Steve Mould'sDöbereiner's lamp (yes, the same Döbreiner as the periodic triads) in my pocket.
See, it's funny because this is a very rudimentary version of a mass spectrometer.
The person is the aerosolized sample atom which is ionized via balloon charging, accelerated by running and jumping, deflected via the magnet, and detected by position on the target on the wall.
Today's post was submitted by Katelynn J, one of my AP chemistry students. As a sub assignment after the AP chemistry exam, I had students submit two posts for this blog. I'll be posting them over the next few weeks.
During COVID-19, this cartoon was probably especially relatable, since everyone was trying to stay as far away from each other as possible. Of course, staying healthy and safe is much more important than adhering to the buddy system, but when going into two separate cars, you’re sure to miss your travel companion at least a little.
In this specific comic, however, the problem isn’t social distancing, it’s Hund’s Rule. On the rail, representing the shells of the QMM, electrons after first fill up all empty spaces before being able to double up, since this stabilizes the atom. The two electrons here trying to enter a car together would make the atom unstable, so it’s better they stay apart.
Katelynn added that "I learned that Hund has more than one rule! His rules are best for the ground state of an atom, and all three have to do with electrons," and she found this website helpful for further reading.
Today's post was submitted by Katelynn J, one of my AP chemistry students. As a sub assignment after the AP chemistry exam, I had students submit two posts for this blog. I'll be posting them over the next few weeks.
Following the death of Pope Francis, a new pope now needs to be chosen. 16-20 days after the mourning period for Francis, elections have now begun and ended, and cardinal Robert Prevost, now Pope Leo XIV, has been chosen. During this selection period, all cardinals under the age of 80 travel to the Vatican to vote, and they are isolated from society until a decision is made. In order to keep the outside world updated, after every vote, ballots are burned and either black {indicating no decision has been made} or white {indicating a pope has been elected} smoke “billows” from the chimney of the Sistine Chapel. Interestingly, the longest conclave took 3 years, following the death of Pope Clement IV in 1268.
But fire only produces one color of smoke, normally. So how are the two colors created? Originally, white smoke was made by the burning of the ballots and the addition of dry grass for a lighter smoke color, and black smoke was made by ballots, wet straw, and rosin to darken the smoke. In modern times (after 2005), a mix of chemicals are used for each color. Chemicals listed here.
This chemical cocktail works because of the state of matter changes that occur. When a substance, like the chemicals used, is vaporized (fire does that!), the particles will recondense in the air, blocking light and only allowing some colors through, the color of smoke that we see.
Learn more about how other non-white/black colors of smoke are made at this link.
Today's post was submitted by Aleeyah B, one of my AP chemistry students. As a sub assignment after the AP chemistry exam, I had students submit two posts for this blog. I'll be posting them over the next few weeks.You know when you cut a piece of fruit and it turns brown after a while, or a banana peel? This article explains how to stop this from happening. This is actually because of a chemical reaction called oxidation. Fruits contain an enzyme called polyphenol oxidase, also called PPO. When the fruit is completely intact, everything stays inside the peel. However, if the fruit is bruised or cut, oxygen in the air goes into the fruit. The enzyme I mentioned before, PPO, reacts with oxygen and turns into something called melanins. This causes the browning we see. This process is called enzymatic oxidation. So the article just explains ways to slow this oxidation reaction.
I found it interesting that fruits turning brown does not necessarily mean that it is going bad. I always viewed brown fruits as spoiled, but now I might view that differently.
Today's post was submitted by Aleeyah B, one of my AP chemistry students. As a sub assignment after the AP chemistry exam, I had students submit two posts for this blog. I'll be posting them over the next few weeks.
We use soap every day, I hope, but we rarely stop to think about the chemistry of it. This source tells us that soap is made when a fat or oil made of triglycerides (fat found in blood) reacts with a strong base such as sodium hydroxide. This reaction breaks down the triglyceride molecules and makes something called glycerol (a sugar alcohol) and what we call soap. Every soap molecule has two ends, one hydrophilic and one hydrophobic. The hydrophobic end attracts to the oil and grease (non-polar), while the hydrophilic side attracts to the water (polar). As we wash our hands, the soap is able to grab the oil, but is also able to be washed away by the water.
Something that I thought was funny was that soap doesn’t just murder all the germs on your hands, but actually washes them away. I always thought soap instantly killed any bacteria it touched, and not necessarily washed them away.
You can learn more about saponification at this link.
I wouldn't normally turn to Fox News for my science reporting, but their story does the best job - of the ones I quickly searched on YouTube - of explaining the Kopp-Etchells effect in which the edges of helicopter rotor blades get abraded via airborn grains of sand, sending showers of pyrophoric tittanium-nickel alloys into the air and making for a lovely light show - that admittedly shortens the lifespan of the blades and advertises the presence of the helicopters at night.
Effectively, it turns the edges of the blades into sparklers.
It makes for some really pretty pictures, though...
Try something fun and see if you can put the periodic table elements in order.
In this game - linked here - you're presented four element names, and you're supposed to click on the element that comes next on the periodic table.
For example, you'll start with four options and should choose Hydrogen because that's the first element on the table. From there, you just choose which of the four presented elements comes next.
I've only played it once, and I got knocked out at #62 - which made me kind of sad, I'll have to admit.
(And please don't buy the linked NFTs of the elements. NFTs are dumb.)
I actually remember the story of the Bhopal accident appearing on the news when I was a child. I would've been about 9 1/2 years old at the time.
There's nothing but tragedy in today's story, an industrial accident in Bhopal, India where a Union Carbide plant producing two pesticides had a huge leak leading to more likely more than ten thousand immediate deaths.
There's not a huge amount of direct chemistry in today's video - in spite of a couple of chemical structures being shown - but there is something I want to say.
(Warning...heavy soapbox moment here...feel free to skip this if you don't want to hear Mr Dusch's very heavy handed opinion.)
We can never have enough corporate oversight by government inspectors.
There are people who will tell you that corporations can police themselves, that they will always take care of safety because it's their people who are in danger.
That's an absolute lie.
Corporations are concerned about profits over everything else. That's it. That's all.
Every corporation lobbying to cut regulations on their production control, every corporation arguing that safety constraints are hurting their business, every corporation trying to cut environmental laws because it hurts their business is putting your life at risk.
They don't care about your life or mine.
They care about profit.
(Oh, and happy fiftieth birthday to me today. I probably should have chosen something a little more happy and light-hearted for today's topic.)
I assume that the full NatGeo documentary goes on to explain what happened near Lake Nyos that day, but the clip I embedded above - the only one I found from NatGeo on YouTube - cuts off before an explanation.
I'll let you make a guess as to what caused all the deaths before you click through to more detailed videos after the jump.
Let's be honest, we should all be more skeptical about videos that we see online.
Yes, there are some really cool videos online. Some of them are real, honest videos of things that actually happened.
Others, however, are bullpucky like the above video of a young woman supposedly pouring boiling water out of an electric kettle and the water freezing into a free-standing spiral before it hits the ground.
This is mocking - or maybe just playing off of a real effect in which boiling water - if thrown into ridiculously cold (like -30 F) air - can freeze before hitting the ground. It does require the water to be nearly aerosolized into really tiny droplets, drastically increasing the surface area allowing for much faster cooling...more on that tomorrow (ooh, a teaser!)
As I said, we should be skeptical. I don't know, however, that we all need to take that skepticism to such mathematical, analytical depths to publicly debunk such videos.
The space cup works with surface tension to keep the liquid in the cup and allow astronauts to drink from an open container rather than from a straw attached to a baggie of liquid.
There's a relatively new development in cars that I've never quite understood: start-stop systems.
That's when stopped cars - at a red light, for example - automatically turn their engine off and start up again when the driver tries to get the car moving again. According to this video - which cites research articles - it only takes about seven seconds of idling to use up more fuel than it takes to simply turn the car off and restart it.
It's almost like engineers know what they're doing.
I've know the broad strokes of the mercury-hatter connection for a while but not the specific details and history that are retold in today's video.
Sounds like the hatter/Danbury shakes were a very early version of lack of workplace protections. The hatters might as well have been told to lick their radium paintbrushes.
The Royal Institution is a British group founded in 1799 and historically known for promoting and sharing scientific knowledge both within scientific circles and to the general public.
Since 1825 they have been putting on a series of Christmas lectures, many of the most recent of which have been recorded and posted on YouTube for us to see.
This video is the 2014 Christmas lecture going through a fair portion of the periodic table, telling stories about each one and helping us to understand a bit of their arrangement along the way.
As promised last week, here's the first Veritasium video about thermite.
I'm not thrilled that Dr Derek's titles seem to be getting more clickbaity and less informative. Again this week, the video's title isn't really what the video is about. It's a minor part of the video - here addressed in about six minutes in the middle of the video - and doesn't really cover the bulk of the video's content.
With that being said, seeing thermite in slow motion and through glass is pretty stunning.
The title of this video - which might change since I'm writing this up just a day after it was posted to YouTube - is a bit misleading. The actual question in the title - why don't railroads need expansion joints - is only answered in the last half minute or so of the video and is answered more thoroughly in a Practical Engineering video that I'll post after a jump.
The bulk of the video is spent explaining how railroad welds using thermite work. The video explains the nuances far better than other thermite videos I've posted before, explaining why the rails must be aligned and peaked, why the rails must be preheated (including a nice demonstration of heat treating), how the crystal structure changes as a result of the weld, and eventually why the rails don't need expansion joints.
This is the second of at least three thermite videos from Dr Derek. I thought I'd posted the first video to both blogs, but I can't seem to find it, so it'll likely show up next week.
I've posted about plasma before, specifically from Veritasium. That video does a great job explaining why halved grapes - and other similarly sized, primarily water objects - can create plasma in a microwave oven
Today's video looks at why plasma can be created from non-water systems like matches under an upside-down beaker, something I've tried before and can verify the ease of it working.
Just to protect myself legally, don't try this at home. Be smart, folks.
Most hand manufacturing processes are stunning to watch, and in this case it apparently produces a product that is superior to mass manufactured competitors. It has to be way more expensive and time-consuming, though.
This video was published by Adam Ragusea in November 2024 about a study from a month or so earlier than that.
The tl;dr of the study is that many black plastics are produced from recycled black plastics that are frequently sourced from electronic waste which contains higher amounts of particularly toxic, flame-retardant chemicals. Those 'new' black plastic items could - especially if used in high heat areas like food flippers and turners on the stovetop - release higher than safe amounts of those chemicals.
In the above video, Adam goes through the possible concerns that this raises as well as noting a possible math error in the study's calculations suggesting that the level of concern is slightly lower than the authors might have initially suggested.
The article was corrected - noting exactly the math error that Adam suggested, and Adam published a spectacular video explaining why that error should not undermine faith in the scientific process or even in the researchers and authors of the original article.
I remember this happening to me in a chemistry lab at Wabash. We didn't got 45 minutes, of course, but I know that we kept thinking there should be a color change by 'now' based on the other titrations we'd done and adding a drop of phenolphthalein just to make sure.
The flask turned bright fuchsia, and we dumped out that trial.
I'll admit that Alec, the host of Technology Connections, might be a little more bothered than is reasonable about the harshness of blue and green LEDs during the holiday season, but he's at least trying to do something about it. (check the videos after the jump)
In this video, he celebrates the fact that a company is now producing warm white LEDs inside multicolored plastic (or maybe glass) bulb covers resulting in something more akin to the same colors as produced by the incandescent filaments inside colored glass bulbs of yore.
I do agree that the blue and green LEDs can be harsh, and the flicker can bother me at times - don't get me started on the LED bar light in my guest bathroom - but mostly I just grumble and move on.
The octet rule is a simple 'rule' that generally describes the behavior of elements in compounds: atoms are most stable when they have eight valence electrons.
But like every rule that humanity has come up with to describe the world around us, nature doesn't give even a little thought to following that rule. Nature does whatever nature does and our rules be damned.
As such, the octet rule is followed far more frequently that it is violated, but there certainly are compounds that don't follow the octet rule.
This guy does a lot of things that I don't think I should do.
My wife has, admittedly, suggested that she might be interested in buying a freeze dryer. It's not something that's come up more than once or twice, but it's been mentioned.
Clearly buying a freeze dryer would be bonkers and nuts. We don't need it. The energy spent isn't remotely worth the very, very few times we'd ever use it before letting it sit unused in a closet somewhere.
At least that's my perspective on the thing, and clearly Mr. Technology Connections agrees with me.
Even though the science involved is kind of fascinating.
