Microscale Thermite Reaction

No video

Microscale Thermite Reaction

Рет қаралды 16,182

Harvard Natural Sciences Lecture Demonstrations

2 ай бұрын

Sparks and light are given off in a small-scale thermite reaction when two rusty iron spheres-one wrapped in aluminum foil-are struck together with a glancing blow. The collision provides enough activation energy to allow the reaction to occur, resulting in the formation of aluminum oxide and large amounts of heat. The bright yellow sparks result from microscopic amounts of extremely hot molten iron being thrown out into the air.
For more details on our setup and references for further study, see sciencedemonst...

Пікірлер: 37

@A3Kr0n 2 ай бұрын

I bought two large bearings at a farm rummage sale so I could do this. It took years to rust one bearing. I gave up and threw it into the wood stove. I took it out in the Spring with a good coat of rust forming. Sparks good!

@russellpurdie 2 ай бұрын

That's why in Australian coalmines they don't use alluminium underground in general.

@bataalexander9703 2 ай бұрын

I would have never come up with this idea, although it is so obvious watching from backwards, of course. Thank you!

@scambroselauntrellus3681 2 ай бұрын

"Where should we do the microscale thermite video?" "Let's do it in the gray experiment chamber" "Cool, should I wear gray?" "No, blue."

@r0cketplumber 2 ай бұрын

How many students have smashed digits with a poorly-aimed blow? As for determining if it is actually a thermite reaction, I'd try using a couple lumps of a different oxidized metal, perhaps copper for a nice bright green flash, but the copper may not be hard enough to cause a reaction on impact at reasonable speeds.

@user-xj8wy4uu1q 2 ай бұрын

You could always electroplate

@Muonium1 2 ай бұрын

This is interesting, but is the mechanism truly the Fe2O3 + Al --> Fe + Al2O3 thermite reaction? I'm skeptical. If one takes two polished steel spheres, even smaller than those seen here in fact, and puts a plain piece of paper between them, then smacks the spheres together at even modest velocity, the paper literally pyrolyzes and explodes due simply to the conversion of kinetic energy into heat at the very small collision point. It's a type of energy focusing phenomenon similar but less dramatic to the kinds that Seth Putterman's lab explores at UCLA. So is there really a metathesis reaction going on here, or is the aluminum simply being heated, melted, and burning in air? If there are no small Fe particles left over on the ground, I suspect the latter. Have you checked with a magnet?

@Engineer_Stepanov 2 ай бұрын

Can be use spectrometer for light analyse.

@NatSciDemos 2 ай бұрын

Paper and aluminum foil are very different materials: paper is a carbon-based material that ignites at about 230 C, whereas aluminum foil available from the supermarket is an alloy (usually with iron and silicon) that has a melting temperature of 660 C at minimum. As @Engineer_Stepanov points out, one could analyze the emission spectrum of the sparks to see if it matches up with aluminum oxide. Another test one could do is to smash two aluminum spheres together to see if the same thing occurs as with rusty iron and aluminum foil.

@adrielburned6924 2 ай бұрын

@@NatSciDemosthere is a vid by Action Labs I think, he uses paper and then tin foil. The foil is "exploded" away with a micro shockwave ripple around the hole. I'm not making any claims either way, but just letting you know it works on foil too.

@camojoe83 2 ай бұрын

Hey, there's the magnet idea. Knew someone would pop in with it.

@ice_aspect5847 2 ай бұрын

My best guess here is the same mechanism here is used to ignite the reaction. And that's why this one makes sparks and paper doesn't.

@sakelaine2953 2 ай бұрын

Rock banging based technology is the best

@ozlemelih 2 ай бұрын

She has balls

@ralanham76 2 ай бұрын

🎶 and knows how to 🎶 use them

@WXUZT 2 ай бұрын

Remarkable ! Thank you for your time.

@bl0ccr4fter24 2 ай бұрын

I’m itching so bad to joke about them slapping balls together, but I’m going to resist it as best I can.

@ariannasv22 2 ай бұрын

"More imaginative" thats a polite way of putting it lmao

@cHAOs9 2 ай бұрын

I dont know if that's actually a thermite reaction. I think it's not. Steel balls hitting each other will heat and compress the air between them, creating a shockwave. It works with clean balls and paper too. In this case, it very well may be simply burning the molten base aluminum in the oxygen in the air, and blowing off a tiny bit of iron oxide. Considering the velocities of air, i would be very surprised if the two had a chance to react with each other. Frankly, it would look about the same since either way oxygen is bonding to molten aluminum. In fact, the air oxygen would be MORE energetic since it doesn't have to rip off of an iron. Prove me wrong. I'd love it if this was actually a thermite reaction. Blowing up thermite doesn't usually make the thermite react.

@camojoe83 2 ай бұрын

Recreate this experiment over some clean butchers paper, then sweep the paper with a magnet when done. If you even get one microsphere of iron from it, then it thermited (it's a verb now, sorry)

@cHAOs9 2 ай бұрын

@@camojoe83 True. With possible exception of Fe3O4 magnetic oxide that could result from heated Fe2O3. But that should be easy to see the difference. Good idea.

@camojoe83 2 ай бұрын

@@cHAOs9 the other thing that might be happening here is an oxide detonation. If you watch Taofledermaus shoot those big aluminum blocks he has, there's almost always a good flash on the impact. Doesn't seem to matter what the slug is made of, either. So maybe the rust, the impact, and the foil being slightly oxidized (not sure that's possible? Maybe only on one side?) just makes a little blasting cap when you slam it all together.

@Fr8gm3ntLives 2 ай бұрын

I often have problems with Aluminium oxide collecting on my balls too. I find a liberal application of talc can help with that.

@dornie_donko 2 ай бұрын

Melting skyscrapers

@wisdomoftheshadows 2 ай бұрын

I remember chinese fireworks like this. They called them dragon balls. Hit them together theyd spark.

@camojoe83 2 ай бұрын

Yeah but they were covered in Armstrong mixture if I remember correctly.. at least it was easy to recreate them with Armstrong's and lacquer... I remember those from my childhood. They'd get worn out real good after a while and it would never fail that I'd pinch the hell out of a finger or something trying to slam the last pops out of em.

@wisdomoftheshadows 2 ай бұрын

@@camojoe83 They smelled nice.