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The experimenters fooled themselves by accident, which is a common occurrence in all human endeavours, including science. The scientific method corrects for thi
by jiggawatts 3y ago
The experimenters fooled themselves by accident, which is a common occurrence in all human endeavours, including science. The scientific method corrects for this via peer review and reproduction of experiment results.
The reproductions showed:
1. The ingredients commercially available have iron impurities. The oven baking process causes the iron to separate out, often towards the edges of the material chunks. Iron is ferromagnetic.
2. The LK99 material itself is strongly diamagnetic, which is interesting in and of itself, but obviously not world-changing.
The result of the combination of the above two is that the iron impurity is attracted to magnets, but the rest of the LK99 material is repelled. This makes samples "stand up", but not hover like a true superconductor would. All of the third-party reproductions showed this effect, none showed samples truly floating.
Similarly, the conductivity tests were zeroed badly. True superconductors have a step-change in conductivity, whereas the graphs measured by the korean team showed a rapid change followed by a slower gradual decrease. The lowest resistance they measured was still very high, comparable to metals, not superconductors.
This is a common issue with fringe research into superconductors: the "signal" they're looking for is a step-change in conductivity because it is easy to measure and rare in most normal materials. However, sudden conductivity changes can occur for all sorts of reasons. It's necessary, but not sufficient for superconductivity to be confirmed.
- tomrod 3y agoFantastic explanation. I appreciate your clarity.
- naasking 3y ago> The scientific method corrects for this via peer review and reproduction of experiment results. By reproduction, yes. By peer review, no.
- jiggawatts 3y agohttps://youtu.be/zl-AgmoZ5mo https://youtu.be/zl-AgmoZ5mo
- naasking 3y agoI'm not sure what you think this shows. Peers can "review" a study all they like, but observations always trump alleged expertise. Only consistent, failed reproductions can truly refute a paper.
- declan_roberts 3y agoThankfully the LK99 paper was easy to (try) and reproduce, and it quickly became obvious that it didn't work the way the researchers initially believed. The same can't be said for the other studies that come out and affect public policy which can't be reproduced. And in some cases we can't even get the data to attempt it!
- nuc1e0n 3y agoAll things considered I think the publication and refutation of LK99 were triumphs for the scientific community as it showed the process working as it should. Hopefully someone will one day discover a real room temperature superconductor.
- verisimi 3y ago> The result of the combination of the above two is that the iron impurity is attracted to magnets, but the rest of the LK99 material is repelled. This makes samples "stand up", but not hover like a true superconductor would. All of the third-party reproductions showed this effect, none showed samples truly floating. Thanks for the explanation. But wow, I'm kind of amazed at the simplicity of the error - iron impurities when you are testing for magnetism! I mean, who would have thought this could be a problem, before announcing this to the world?!
- ajdude 3y agoTo be fair, the team itself wasn't planning on announcing this and still wanted to do more experiments and refining before publishing a paper. I believe it was one of the funders for the team got impatient and leaked it prematurely.
- donalbrecht 3y agoThanks for explaining. As with most science news coverage, it was hard to understand this context.
- micw 3y ago> The LK99 material itself is strongly diamagnetic, which is interesting in and of itself, but obviously not world-changing. How strong is it's diamagnetic constant? Is it way more than pyrolytic carbon so that we can at least create fancy, levitating toys from it?
- vGPU 3y agoThe most recent developments state that LK-99 should theoretically be a superconductor as of a month ago, but as far as I am aware, no actual physical replication.