Why Lithium Is Dangerous But PERFECT For Batteries

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.

People said this experiment was impossible, so I tried it

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.

Great video...bad title...

Why copper pans are great (and sometimes poisonous)

I can vouch for that Harold McGee book referenced toward the beginning. I have it on the shelf in my living room - though I'll admit that I've barely read more than a third of it. There's a LOT of science happening in there, and it's a dense read.

Adam explains the basics of heat conductivity, reactivity (leaching ions to make whipping egg whites easier), reactivity again (to pull sulfur out of the vapor distillate in alcohol distillation), malleability (peening the copper bowl), ductility (making copper whisks), reactivity another time (such as the health hazards of drinking acidic cocktails like mules from copper cups), and conductivity again (useful for making jams and candy).

And then he throws down the possibility of testing a pure silver pan...I want him to buy one, but I'm not going to support him to make that easier for him to do.

High demand and prices for lithium send mines into overdrive

Source - NPR article

We need lithium.

We didn't used to need nearly as much lithium as we do now, and we're going to need way more lithium going forward because lithium is used to make pretty much every high tech battery - like those in electric vehicles. Those batteries need a whole lot of lithium.

I've posted about the one lithium mine in the United States and how it's running into conflicts with environmentalists over the destruction of habitat for Tiehm's buckwheat.

Today's article from NPR - which also has a 7-minute audio story in case you'd rather just listen to the story - shows some photos from the aforementioned Silver Peak mine in Nevada and explores other possible sources of lithium including seawater and geothermal power plant brine. Sadly they don't go into the reason lithium is so useful: its position at the top of the activity series and its relative low density making it a great way to store energy in small masses.

Hiding a Nobel Prize From the Nazis

So much chemistry here.

Great explanation of a famous story of Neil Bohr's lab - particularly George de Hevesy - dissolving two gold Nobel prize medals to hide them from the Nazis...and then precipitating the gold back out of solution a decade or so later once the Nazis had been defeated.

It's a great story, and the science - full d-shells, equilibrium, Le Chatelier's principle - is outstanding. The story itself is better told in this NPR post from Same Kean's The Disappearing Spoon book, but Kean doesn't go into the science as well as Hank Green does here. 

How Not to Put Out a Metal Fire - with Steve Mould

I remember watching WGN a couple of decades ago about a fire at a metals recycling company in Chicago (maybe this one?) The thing that fascinated me at the time was watching the firefighters spray water on the fire, have it explode, and repeat the process a couple more times. The fire chief at the time - in my deep memory, at least - said something to the effect that they knew the explosion was likely but that they were trying to dump enough water on all at once to cool the fire enough to stop the burn. Not enough water = explosion, though.

In the above video - the Royal Institute - Steve Mould shows why magnesium fires are such a bear to put out. They don't - as the article linked above says - 'produce their own oxygen', but they do tear oxygen off of carbon dioxide and water. Once that happens, then, the fire allows the hydrogen and oxygen (from water - or oxygen and carbon (from carbon dioxide) to react with the magnesium or with each other producing an even hotter flame.

Hmmm...seems magnesium's active or something.

(And I don't think - at 2:55 - you 'can actually see [the beaker filling with carbon dioxide]', Steve. My understanding is that carbon dioxide is invisible. What I think you're seeing is fog, condensing water vapor due to the coldness of the dry ice.)

Spinning Sphere of Molten Sodium

I know they're not doing this experiment - "12.5 tons of hot, liquid metal designed to spin at up to four revolutions per second" - because of any chemistry questions. Rather they're trying to explore the creation of the Earth's magnetic field.

But because they're using molten sodium, there are some fascinating chemical reactions that they need to avoid.

So they don't have a normal, water-based sprinkler system to avoid 'modestly catastrophic" because water on sodium, to quote Mr Mackey, 'it's bad, mkay'.