Our chemistry book has a diagram of a battery in the electrochemistry chapter, and I discuss that battery for a bit before explaining to my students that the basics of ACME (anode, cathode, metallic path, electrolyte) hold for every battery but that the engineering of modern lithium-ion batteries is far different from the diagram in the book.
This video - again leaning into the algorithm-rewarded longer and longer format - explains some battery basics involving the activity series, the history of the development of the lithium-ion battery, and the methods of fiery failure when the battery overheats.
This is, as Dr Derek says, a technology that has allowed our modern, battery-dependent world.
We'll start with the video debrief of the driver with the armored vehicle manufacturer after the fact so we're all aware that things worked out fine for the people you'll see in the next two videos which are the original footage - first one inside the vehicle, second one a dashcam pointed out of the video.
We've had impressive videos of bulletproof, composite glass before, but this is a really impressive application of that material in its designed use. And, of course, the host sits in the car at the very end while one of his coworkers fires another two shots at him. Nuts, man...
And the final video is from an American morning show providing some context on the interior video that was making its rounds on social media at the time.
Heck of a first day on the job for the guy in the passenger seat.
How have I missed posting this in the blog? I've been using this video for a couple of years to explain that pyrex =/= Pyrex.
I would explain, but honestly, the Consumer Reports host up there does a great job explaining that consumer pyrex isn't the same as lab Pyrex and hasn't been for decades.
Tl;dr - don't take your pyrex casserole dish from the freezer to the oven or from the oven to the countertop.
The membrane described above can block small particles but allow larger particles through, a thoroughly non-intuitive method of filtering.
Then again, water is weird. It holds together, 'healing' itself via intermolecular forces. In this case, the addition of sodium dodecyl sulfate - something I've heard called sodium lauryl sulfate - allows the water membrane to be penetrated and then come back together.
In order to break through the membrane, particles need enough momentum (mass times velocity, natch) to break through the membrane, so larger particles have an easier time to get through. Smaller particles, then, have to be moving far faster if they're going to break through.
And automatically, people go straight to the possibility of keeping the poop smell in a toilet.
I haven't the foggiest idea what you need to do to be safe on a motorcycle. I guess my first step would be to not get on the motorcycle, but that's your call.
The above video goes through the advantages and disadvantages of the various materials used to provide protection in a motorcycle jacket: silicon (1:09), thermoplastics (1:40 - though the description of thermoplastics leaves something to be desired), foam (2:32), and viscoelastic materials (3:27) like d3o (SAS Tec, TFArmor, APS Air [though I think that's basically an airbag]- other brands he mentions).
The host's description of d3o is, however, outstanding. He does mention 'grade three' which is a giveaway that he's Canadian.
I've shown you Line-X before, but I wasn't able to show you the science between the two components of Line-X before. In this video, we get to see modeling of the polymerization at 2:00 using plastic, molecular models (by the way, does anybody know the specific plastic model set that they show up close at 3:34? I really dig that set and wouldn't mind getting my hands on a set to see if they're worth buying.)
That's pretty much what tempered glass is supposed to do right there.
Yes, there may be a quality control issue in that the tempering might be better or worse depending on the production mechanics and controls, but that view of shattering into multiple small pieces is what's supposed to happen with tempered glass.
Ideally, those pieces would be smaller than some of those we see in the video, but that's way better than what untempered glass would cause - a very few large, heavy, sharp glass pieces falling down on the showerers.
What does that guy have against that panel of glass?
Doesn't he understand that he can just slide the aluminum frame out of the way and get to the bricks underneath?
Heck, he could probably just undo the C-clamps, slip the 2x4 blocks, and shift the glass panel off to the side.
ESG glass has all sorts of product options including their Secure line, shown up above. They describe themselves as "the UK's premiere glass processor, toughener, and laminator for the professional trade."
I see all sorts of cool material science happening in that sentence.
I do believe it goes without saying, "don't try this at home."
At 1:40 the host of Outrageous Acts of Science goes through the idea of bulletproof glass, alternating layers of glass and polycarbonate.
Then, at 1:55 we get the money quote, "composites are used when you want the properties of two different materials, and you want to put them together for different purposes."
This isn't anything that I think we'll ever cover in the material science course at Princeton High School. We tend to steer clear of psuedoscience and of pouring molten metal into water.
I do understand, though, that with the mass of metal (tiny) and of water (relatively huge) there isn't going to be a significant change in water temperature, minimizing the temperature change and risk of any water vaporizing and then spitting the molten metal outward at the melter.
I do dig that the melting of metal (or wax - called carromancy - and also highlighted on the page where I found this video) is a New Years tradition in the teutonic world, but I'm a little saddened that it is used as some way to look into the future.
Yeah, the message at 0:14 says, "[PVA] dissolves without leaving any harmless residue." That seems like a double negative - without leaving...harmless. It's a little confusing there, admittedly, but I'm going to chalk that up to Infhidro Soluciones en Film Hidrosoluble isn't a native English-speaking company.
PVA packaging can be pretty outstanding stuff. Just bundle up anything you need to later dissolve into water. Make the package exactly the right amount to be measured out and dosed.
Just don't make it something edible because the PVA isn't exactly something you'd want to ingest.
And maybe don't make the stuff inside the PVA package pretty enough that kids will want to pop the PVA packages like candy when they will then explode like little poisonous bombs in the mouth...sort of like a Detergent Gusher. See, Consumer Reports recently posted that The New York Times reported that in 2012 and 2013, over 17,000 children were poisoned (thankfully some in minor ways) by PVA detergent pods.
And that, my friends, is why you always need to keep your mold totally, absolutely, perfectly dry when you're pouring molten metal. Steam explosions suck.
This is not something to laugh about...unless you're Russian, I guess.
Such cute, bouncy little music from a video about fun, deadly little toys.
Ok, deadly might be an overstatement, but the jumbo growing spheres available from various companies have been recalled because, as written on the US Consumer Product Safety Commission's website...
The soft and colorful product can be easily mistaken by a child for
candy. When the marble-sized toy is ingested, it can expand inside a
child’s body and cause intestinal obstructions, resulting in severe
discomfort, vomiting, dehydration and could be life threatening. The
toys do not show up on an x-ray and require surgery to be removed from
the body.
That's a bit of a bummer as the gel spheres are great in class for demonstrating index of refraction, lensing in an eyeball, crosslinked polymers, and osmosis & diffusion and as a medium for watching seed germination. Some companies - including Education Innovations, a favorite of the ASM teachers camp program - are still selling the spheres in smaller sizes, but it appears that the giant spheres are no longer available because they can sort of stop of the intestines.
The end of August of 2005 saw news in Cincinnati covering a story of a railcar spontaneously polymerizing styrene. The railcar was venting styrene and getting hotter thanks to the exothermic polymerization process.
You can catch a glimpse of the railcar being doused with water from 0:30-0:38 in this video...
The escape of gaseous styrene was observed from a safety valve on a stationary railway tank vehicle on the 28th August 2005 at approx. 5 pm, near Cincinnati at the regional airport Lunken in the state of Ohio. According to media reports, the tank vehicle contained approx. 24'000 gallons, that is about 90'000 liters of styrene. The tank vehicle belongs to a company that has been admitted to official quotation on the stock exchange with an ISO 9000 certification and a safety award "OSHA star site".
...
Because the opening of a safety valve requires an increase in internal pressure, one can assume that an exothermic (heat generating) reaction had taken place inside the tank. In the case of styrene, a well known reaction is the polymerization of styrene to polystyrene.
A stabiliser like 4-tertiary-butyl-catechol (TBC), which prevents polymerization, is usually added to styrene for transport and storage. In order for TBC to be effective, it is necessary that a certain concentration of oxygen is dissolved in the styrene solution besides TBC. Should no stabiliser be present or it has been used up, styrene can polymerize with oxygen to form a styrene-oxygen copolymer, benzaldehyde or formaldehyde.
Between 10-15 ppm TBC is added to styrene. Under ideal conditions, 10-15 ppm TBC stabilises styrene for approximately 3 months. The TBC can be used up faster according to oxygen concentration, temperature, humidity, rust or other impurities in the tank. In addition, a minimal oxygen concentration of 10 ppm. and preferentially of 15-20 ppm. is necessary.
The higher the temperature is, the faster the TBC concentration falls.
...
According to media reports, the tank wagon had been stationary at the site of the accident for 9 months. Due to this lengthy stationary period, the polymerisation would be likely to account for the rise in pressure.
Aristatek's website uses the incident as an example of a training document...
What caused the rail car to vent styrene monomer? The venting occurred because of an
increase in pressure inside the tank. The website listed above explained that the increase
in pressure was due to heat generated within the tank due to
polymerization of the styrene
monomer within the tank. Normally, a chemical inhibitor
such as 15 parts per million of
4-tertiary-butyl-catechol (TBC) is added to the tank during transport to prevent
polymerization. This inhibitor scavenges rust and other impurities within the tank that
can act to initiate polymerization. Oxygen (about 10 ppm) is
also required to be
dissolved in the styrene monomer for the TBC to do its
job. The TBC concentration
decreases with time as it scavenges impurities; 15 ppm concentration would probably be mostly used up in possibly 3 months (even less time if ambient temperatures are warmer).
The website mentioned that the rail car had been sitting there for 9 months. Without the
inhibitor, the styrene monomer can polymerize with oxygen to form a styrene-oxygen
copolymer or benzaldehyde and/or formaldehyde and polymerize
with the release of heat.
The heat further accelerates the polymerization releasing more heat.
Fortunately, no explosion occurred, the chemical was not released all at once, and people
were evacuated to safe distances. The safety valve did t
he job it was designed to do, to
release excessive pressure buildup slowly avoiding a catastrophic explosion. The error
was that the rail car was allowed to sit there for nine
months, during which time the
inhibitor became depleted.
The Cincinnati Enquirer's website provides a day-by-day recounting of the entire event...
I'm going to let Michael Smith describe this incident...from his Google+ page...
Many of your know that I work at a steel mill and here one example from the video below of the dangers we face daily. The West Camera shows the danger to workers from the explosion. If you watch carefully on the EAF Tapping Camera, you can see the water bottle get thrown into the ladle causing the explosion.
The root cause of the incident was a partially filled water bottle was thrown into the ladle just after tapping and must have gone below the surface of the steel very quickly.
We are very lucky that no one was injured, and it’s difficult to see but we had one of our operators on the sump (at the top of the stairs) at the time of the explosion. The 2 views are the tapping camera and then the view from the camera at the LMF which gives you a perspective of the size of the explosion.
I'm curious about the second view that he mentions, because the post has only one video posted, but I'll look around for that later.
Nothing much happens for the first twenty five or so second, then a water bottle is thrown in from the right, and everything goes the H-E-double-hockey-sticks.
I spoke to a former steel mill engineer (not at this mill) about this incident, and her explanation was that the water turned to water vapor - with accompanying volume increase. A different metallurgist, however, said he thought that the heat of the molten steel caused the steelto grab the oxygen from the water, leaving behind explosive hydrogen.
Either way, it's further proof that I do not want to work in a steel mill.
"This is basically a do-it-yourself fire blocker..."
Yup, that's about right.
The comparison of the untreated and untreated sides of the 'house' is stunning, and the application of the sodium polyacrylate is absolutely brilliant.
I'm stunned that the host has the faith to put his Barricade-coated hand over the torch. That's some faith in the product.
If I lived in a different part of the country (not in southern Ohio, as I am), I'm thinking I would stock Barricade by the tankful.
