The lead sponge mystery continues...

"Remember, viewers at home; The difference between Messing Around, and Science, is Writing Things Down."

Metallurgist here. The white film or coating on the cast iron is from vaporized zinc. You have two samples that did it and both had zinc. You can get this same effect from over heating brass on any other zinc filled material . Also it's the last step in the parkes method for silver extraction to heat the zinc and silver mix until the zinc vaporizeses off.

set it on fire throws it in water and acid keeps getting different reactions "What are you?!"

"Placed on this cast iron, cooking thing", sweetie thats a pan

I love these real science videos. It's like a "let's play" for chemistry, we get to watch the actual scientific process.

Lead sponge for when you need to poison your dishes

When you're checking for conductivity don't use the "continuity" setting on your multi meter, use the ohm setting (resistance) and you will be able to get a numerical value for the conductivity.

See if you can make sheets of it with embedded copper, gold, or aluminum wire and see if it can be used as a lead acid battery. The extreme surface area might augment its ampere output. It would be an interesting experiment.

"place on this little, cast iron cooking thing" cute XD

Why is it that I fall asleep in chem class, am reluctant to do chem homework on Aleks.... but I'll watch these videos all day long? Thanks for making the subject interesting. Keep experimenting!

There's something that happens to plant roots that might explain why you can't respongify it after its dried. When you take a cutting from a plant and put it in water to grow roots, a very fine network of hair-like roots fans out in the water to maximize surface area. It's difficult to transplant a water rooted plant into dirt, because when you pull the roots out of the water they all clump together because of the surface tension of water, and they don't spread back out when you plant it in dirt. New roots have to grow to replace the ones that are stuck together. When you dry out the sponge, all of the very delicate suspended filaments of crystals get tangled into a crystal-like matrix as the water leaves and eventually they lock together when dry. Rehydrating it doesn't untangle the knots

Hypotheses: 1) The acid treatment removes the zinc leaving behind a dry cake of lead. The lead particles are separated by a lot of air and loosely held together by friction so it takes very little heat to melt the fairly pure lead sponge. 2) Looked blue/grey/white to me but maybe a coating on the pan? 3) Different reactions by the different lead and zinc compounds, salts, oxides. Impurities, uneven heating, trapped liquid. 4) The zinc is intertwined in the lead matrix. Ties in to 3. Imagine if you soaked an actual sponge in water and tried to evaporate the water (lead) with a blowtorch. You’re going to burn the sponge (zinc) before the water inside (lead) evaporates (melts). If you take the zinc out of the equation the process is simpler. 5) There’s no elasticity to the lead matrix so it only compresses. The only thing keeping it “spongey” was the liquid separating the particles. Once dry, when placed in liquid some will fill the holes but unless it’s soluble in the liquid then it will stay “set.” Similar to porous cement or a sponge that’s crusty and super old. 6) See 5 and 7 7) Both, sort of. Like trying to bring a piece of beef jerky back to pre-jerky freshness.

I immediately wanted to know how long you could maintain a stable sponge, or if it hardens over time even in water.

I think that you woudn't been able to melt your first piece was caused by the oxide layer and sponge-like nature of the chunk. When you blasted it with propane torch, you created a thin layer of lead oxide (which have higher melting point i think) and, because of air pockets (just like in aerogel) behind this non-meltable layer you've made a pretty heat resistant material. It would be great to create flat-ish piece of lead sponge and measure temprerature behind it while blasting it with torch.

5:40 "I placed it on this little cast iron cooking thing and continued eating it." Wait what

Maybe when it dries the sponge matrix collapses (since it's so soft) destroying it's ability to absorb moisture. It would be interesting if you could replace the water with oil.

I like it? Yea I understand it? Hell no

Could you possibly do a video of the equipment your ‘lab’ consists of and the level of education you have that allows you to do all these amazing conversions and demonstrations?

13:30 is actually a new years tradition in my country you pour the lead and then try to identify shapes wich are assigned a certain meaning, that's sorta like fortune telling^^

Now this is some real classic honest-to-goodness chemistry.