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Aardvark Daily

New Zealand's longest-running online daily news and commentary publication, now in its 25th year. The opinion pieces presented here are not purported to be fact but reasonable effort is made to ensure accuracy.

Content copyright © 1995 - 2019 to Bruce Simpson (aka Aardvark), the logo was kindly created for Aardvark Daily by the folks at aardvark.co.uk



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The more we learn...

9 September 2021

The sci-tech news wires are buzzing with reports of new records being broken in the area of magnetic fields.

In the quest to create clean, green, almost inexhaustable power from the fusion of hydrogen in a reactor, researchers have built the world's most powerful magnet in the form of a 20 tesla unit.

This hefty piece of kit will create fields that help contain and compress the uber-hot plasma flow that is needed to create fusion.

News of this kind of got me thinking today.

As a kid, I always found magnetism to be a fascinating thing.

Of course when I started playing with magnetism we only had relatively weak permanent and electro-magnets to play with.

You could buy magnets for messing around with. They were usually just a piece of iron that was formed into a horseshoe shape and painted red. To be honest, they were pretty crappy. If you were lucky they'd be strong enough to pick up a nail -- but that was about it.

You could feel the forces of magnet attraction but only barely.

I did a lot of experimentation with magnets. I read that you could actually magnetise a piece of iron by pointing it from north to south and then repeatedly whacking it with a hammer. Guess what... it works!

Many, many hours were also spent winding multiple layers of thin wire around nails, bolts and other bits of ferous metal so as to create electromagnets of varying strengths. I shudder to think about just how many C cells and D cells gave their lives to these experiments but it was a good number.

It wasn't too long before I discovered that small DC electric motors, such as those found in some of my toys, were a much better source of magnets. The magnets in these things were either made of an alloy called Alnico (made from alumninium, nickel, cobalt, iron, copper, titanium and niobium) or ferrite. They were much stronger than those piss-weak iron magnets I'd been playing with earlier.

These days however, neodymium has changed the game completely.

Permanent magnets made of this rare-earth material are generally about ten times stronger than those made from previous generation materials.

In fact, larger neodymium magnets are downright dangerous and are not the sort of things I'd give to a kid to play around with.

The really interesting thing about all this magnetism stuff is that, as far as I understand it, we really don't have a total grasp of exactly how it works. Whilst it's true that we understand enough to use magnetism and create magnets for our own uses, at the most basic atomic and subatomic level, there's still a bit of murkiness.

The subject of magnetic monopoles, for example, is an interesting one. Some research says they can't exist, others say they can in theory but by their very nature, they will be extremely rare.

It surprises me that some of the most basic forces of nature such as magnetism and gravity, remain so mysterious. We take them for granted and rely on their effects every moment of every day -- but most people could not explain what creates them.

In fact, we have very little solid, hard knowledge of the quantum world, from where these forces seem to spring. Theories to try and describe the quantum world abound, but there are many areas of disagreement and still huge gaps in our knowledge.

I guess we'll have to wait a few more centuries before we get warp drive and time travel.

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