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This is a neodymium magnet - it's pretty darn strong.
这是一块钕磁铁——相当结实。
And now, after heating it in a flame ... it's no longer magnetic.
现在用火焰加热后，它不再具有磁性。
What just happened? Well, to build a magnet, all you need to do is find a bunch of magnetic atoms
刚才发生了什么？嗯，要制造一块磁铁，你只需要找到一堆磁性原子，
(that's easy - they're the ones with half-filled electron shells in the middle of any of the major blocks of the periodic table)
（这很容易——它们具有半个电子壳、位于元素周期表任一区域的中间位置）
and then make a compound where the magnetic fields of the atoms align in the same direction -
然后制造一个化合物，使原子的磁场沿同一方向排列——
this is Ferromagnetism, named after Iron, which is pretty darn magnetic.
这就是以铁命名的铁磁性，它具有相当大的磁性。
However, it's not always so easy - sometimes the atoms actually want to align their magnetic fields in alternating directions -
然而，这并不总是那么容易——有时，原子想要在不同方向上调整它们的磁场——
this is called "anti-ferromagnetism" and it means the bulk material won't have a magnetic field at all.
这就是所谓的“反铁磁性”，这意味着材料根本不会有磁场。
Or, sometimes the tendency of the atomic magnets to align (or anti-align) is just too weak to overcome their intrinsic jiggling - that is, their temperature!
或者，有时原子磁铁调整（或反调整）的趋势太弱而无法克服其固有的抖动——这就是他们的温度！
In which case, even though all the individual atoms in the material are magnetic, once more the material as a whole isn't.
在这种情况下，即使材料中的所有单个原子都是有磁性的，整个材料还是没有。
However, in a strong external magnetic field, the atoms do tend to align with each other in the direction parallel to the field.
但在强外部磁场中，原子确实倾向于在平行于磁场的方向上相互调整。
This is called "para-magnetism," and liquid oxygen is a great example - it's attracted by a magnet,
这就是所谓的“顺磁性”，液氧就是一个很好的例子——它被磁铁吸引，
though it doesn't stay magnetized afterwards.
虽然此后并不会保持磁性。
But let's get back to the question - how do you destroy a magnet?
我们回到那个问题——如何毁掉一块磁铁？
Well, a material can only be ferromagnetic if its temperature is low enough:
嗯，只有温度足够低的材料才能是铁磁性的：
above a certain point, the nicely ordered atomic magnetic fields "melt" into disorder,
在某一温度之上，排列整齐的原子磁场会“融化”为无序状态，
just as ice crystals melt into water when heated past zero celsius.
就像加热到高于零摄氏度时冰晶融化成水一样。
So to destroy a magnet, you just need to heat it up past its "magnetic melting poin", called the "Curie Temperature" -
因此，要毁掉一块磁铁，你只需将其加热到超过其“磁性熔点”（它被称为“居里温度”）——
it probably won't look like much is happening, but once the atoms are jiggling around enough, when they cool off,
看起来好像并没有发生太多变化，但一旦原子摇摆得足够近，当它们冷却时，
their magnetic fields will no longer all point in the same direction. Magnet destroyed!
它们的磁场将不再全部指向同一方向。磁铁被毁掉了！
And just as different elements melt from solid to liquid at different temperatures,
正如不同的元素在不同的温度下从固体熔化成液体一样，
they also melt from being ferromagnetic to paramagnetic at different temperatures,
它们在不同温度下也会从铁磁性转变为顺磁性，
which you can explore in this sweet interactive periodic table, which also plays all of the Periodic Table of Videos.
你可以在这个交互式周期表中进行浏览，它还能播放所有的周期表视频。
We're going to begin with an experiment ...
我们先做个实验……
This episode of minute physics is supported by audible.com,
这期一分钟学物理由audible.com支持，
the leading provider of audiobooks across all types of literature including fiction and nonfiction and periodicals.
这是一家小说、非小说和期刊等各类文学有声读物的领先供应商。
To delve deeper into the stories and science behind the periodic table,
为了更深入地了解元素周期表背后的故事和科学，
check out the disappearing spoon and other true tales of madness, love and the history of the world from the periodic table of the elements by Sam Keen.
请从山姆·基恩的“元素周期表的元素”中查看消失的勺子以及其他有关疯狂、爱与世界历史的真实故事。
Man that's a long title. You can download this audiobook or another of your choice for free at audible.com/minutephysics.
天哪，这个名字可真长。你可以从audible.com/minutephysics上免费下载该有声读物或你喜欢的其他有声读物。
Again, thanks the audible for making it possible for me to keep producing minutephysics and for giving you a free audiobook at audible.com/minutephysics.
再次感谢audible，它支持我一直制作一分钟学物理，并为您提供免费的有声读物。
