Dr Vetrovec intends to perform his version of the trick at atmospheric pressure, and using permanent magnets.

维特威克要在大气压力下使用永磁体来实现他的这种把戏。

This makes electromagnets quite different from permanent magnets.

这使得电磁体与永磁体有很大不同。

This is different from a permanent magnet because permanent magnets don't need this wire.

这与永磁体不同，因为永磁体不需要这种电线。

So let's take a look at that and compare permanent magnets to electromagnets.

看一下并将永磁体与电磁体进行比较。

Permanent magnets also have fixed poles.

永磁体也有固定磁极。

On the other hand, permanent magnets are always on.

另一方面，永磁体始终处于开启状态。

Permanent magnets have a fixed strength, but we just talked about how we can change the strength of electromagnets, so electromagnets have adjustable strength.

永磁体的强度是固定的，但是刚才讲了如何改变电磁铁的强度，所以电磁铁的强度是可调的。

Permanent magnets do not need a power source, but this means that we can also turn electromagnets on and off, which is pretty cool when you think about it.

永磁体不需要电源，但这意味着也可以打开和关闭电磁体，看，这真是太酷了。