Yesterday I wrote about a rare earth material called gadolinium that loses its attraction to magnets when it reaches room temperature. And I wondered if you could use this strange phenomenon as the basis for a generator. I thought it was obvious that a device depending on outside heat was not a perpetual motion machine any more than a wind mill is, but but many of you left comments to clarify that point. Apparently my writing was sloppy because the earlier paragraphs were about perpetual motion and I didn't call out the transition to non-perpetual motion and the gadolinium generator. In the interest of clarity, the rest of this post is NOT about perpetual motion in the strictest sense.

Someone pointed out that gadolinium doesn't lose its attraction to magnets; it just becomes less of a magnet itself, but would still be attracted to magnets like metal. There appears to be some conflicting information on the Internet on that point. The stuff I read indicates that a warmed piece of gadolinium wouldn't be attracted to a magnet in any fashion. Your unreliable strangers might be more reliable than my unreliable strangers.

But here's the interesting part. When you expose gadolinium to a magnet, it heats up. That property has been used to create refrigeration, although I don't see any recent articles about it. http://www.eurekalert.org/features/doe/2001-11/dl-mrs062802.php

So if what I read on the Internet is correct (which seems hugely unlikely) you could build a (nearly) perpetual motion device using a natural magnet and gadolinium as long as you could control the room temperature without any extra energy. Here's how it would work: Imagine a natural magnet suspended over a piece of gadolinium in a room that is just below room temperature. The gadolinium is attracted to the magnet and jumps from its resting point to attach to the magnet. Now the gadolinium is experiencing a stonger magnetic force, and according to its natural and unique properties, it heats up. That extra heat puts it above room temperature and it becomes suddenly unattracted to the magnet, falls off, and begins to cool. And repeat, forever, or until someone opens a window.

I suppose you'd use more energy keeping the room at the right temperature than you'd create by the process. But still, if it worked outdoors for half an hour every day, as the world went from cool to warm, in certain climates on certain days, it would still be nifty.

Clearly this won't work, or you'd have a toy like this on your desk as a novelty item that only operates when the room temperature is in a particular range. So I assume I am misinterpreting the qualities of gadolinium. But that doesn't make it any less fun to think about.
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Dec 13, 2012
As someone who's been looking (and mostly laughing) at alt-energy for a long time, I can tell you this absolutely won't work as a generator (though it might move for some time). There have been about a million attempts to build magnetic generators similar to this and they never, ever work (though some do attract impressive levels of funding from stupid people). Magnetism doesn't work this way; it's a First Law problem.

Here's why, in a nutshell: what you have is two gradients, one gravity and one magnetic. Your proposed generator would harness energy by falling down one gradient, then the other. The problem is, to move down in one gradient you have to also move up in the other, and <i>it always takes work to move up a gradient.</i> The 1LOT mandates that the energy required to re/demagnetize the gadolinium must always be more than what could be generated from the movement of the gadolinium.

It should be pointed out, btw, that building a "nearly perpetual motion machine" that <i>doesn't generate energy</i> is trivial -- all you have to do is take some matter that has a nonzero temperature, and put it in an insulated box. It will bounce around in there for quite a while (though 2LOT says not forever).

The one <i>possible</i> plausible exception I've run across is something called a Mach drive, which works on a similar principle - there are certain materials that seem to undergo a mass change under certain conditions, and this can be used (in theory) to generate thrust. The critics argue this is a 1LOT violation because above certain efficiencies you could build a generator that way, the supporters argue there is no 1LOT violation because the Mach drive/generator borrows momentum from the causally connected universe. There's a Dr. Paul March who has produced some interesting test results, I believe up to a milli-newton now, though replication is lacking.
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Dec 12, 2012
In my recent research i found they have come up with a blend of other metels that allow gadolium to work at room temp a few google searches and you'll find it also it seems to be able to reach 80 degrees F I have been wondering about ways to use it to preheat water before it enters my on demand hot water heater
Jun 6, 2008
IF gondolinium goes from non magnetic to magnetic at a specific temperature (the way water won't boil at 99.99 C* but will at 100C*) then theoretically you can use friction to produce the minute increase in temperature needed while the correct outside temp would balance the heat produced (Gondolium would change temperature as little as possible for best efficiency). This almost seems plausable but i don't believe in perpetual motion so somebody tell me what's wrong with it?
May 29, 2008
Being totally lazy and not wanting to do any real research, I have to ask the question: why do we need it to be in a place near room temperature? Why not northern Canada or Siberia?

Regardless of how quickly the gadolinium heats up, it should not need to heat the entire area to lose its magnetic properties, only itself and a small "orbit" around it. Once it heats up to room temperature it would release, but in natural low temperatures, it would quickly cool off and re-magnetize.

I've done enough heavy thinking for the day.
May 27, 2008
I must have gadolinium in my system, my attraction to women fades away as they approach room temperature.

Or, it could be their lack of a pulse that makes me want to drift away.

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May 24, 2008
The room? Why not keep your Gadolinium device in a small chamber, assuming it works the way your unreliable strangers say? You'd have more control over the device's temperature and thereby its function.
May 23, 2008
More detail here:

May 23, 2008
No, you can't create energy this way. What you've described is essentially the same as the "Free Electricity" scam companies like Sonship have been peddling for decades: power from permanent magnets. Using gadolinium's properties doesn't really change that.

Essentially, the problem is that the motion from the permanent magnet is not free; they demagnetize after produing a small amount of energy, because magnets are very inefficient storers of energy.
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May 23, 2008
I realise i'm sounding like one of my cow-workers here but....

How can a room be just below "room temperature". The temperature which the room is curently at makes the current room temperature the "room temperature" variable. Therefore your room cannot ever be at anything other than at "room temperature". Your fridge will be below room temperature say for example 3C but say your whole room was the inside of the fridge then that 3C would be "room temperature". Thus making it impossible to have the gadoliniumat anything but at room temperature whilst inside the room.
May 22, 2008
I would like to see the comments sorted by votes descending as the default.

The mashups ARE pretty good.

Interesting how people react to change.
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May 22, 2008
well I think this might be relevant and interesting... i decided to do a quick check through google's patent index for the refrigeration motor that you described and guess what i found... your magnetic turbine


and there is the patent to prove it. its been around since 1984 but it seems like an interesting and cheaper way to generate power than these non-renewables that we currently use, but i am not an electrical engineer so i could be way off base... but there is your patent Mr Douglas
May 22, 2008
There may be another reason why we don't have gadolinium novelty items on our desks; it may be fun, but it's also poisonous. :-)

(According to those same unreliable strangers, that is: http://en.wikipedia.org/wiki/Gadolinium#Precautions)
May 22, 2008
Quit feeding me knowledge! I'm on day 1 of a mini-vacation, and was hoping to give my brain a timeout. But now because of the curiosity OCD I'm going to be looking up this gadolinium right after this instead of looking up the nearest place I can get a Gin Fizz. Dammit! :)
May 22, 2008
I suspect you could conquer the "room temperature" issue by building this thing in a large cave... or simply building it underground.

If I remember correctly, caves tend to maintain a remarkably stable temperature year-round... though I'm far too lazy to look it up and confirm.
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May 22, 2008
Love your strip today. I have a friend who is like that woman.
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May 22, 2008
Hi Rita Mae,

I have to comment,

IVIL asks --- [i wonder why you went down to 38 comments a day from approx 150?]

Rita responds --- May I suggest that it could that people don't like to be rated?

I think it is the mashups. There are some pretty funny people out there, I actually spend some time reading them. I do look forward to the time when Scott republishes them in a book or online game of some sort, (find the original strip or something like that) and everyone goes crazy demanding royalties or threatening law suits.


PS: send me some virtual cake from your retirement party.

May 22, 2008
Okay, Scott. Enough with the perpetual motion. It might be fun to think about, but so is invisibility.

BTW, invisibility will soon be possible:

May 22, 2008
Hi Scott,

It's fine if you like thinking about things that don't actually work, but some of us like thinking about things that do actually work, and like figuring out why it is that certain ideas won't work.

You're a trained economist, so you understand. You feel the need to speak up when someone says they like the idea of a gas tax holiday. Some of us are like that, with our field of study.

And your gadolinium idea wouldn't work. It couldn't generate enough heat, internally, to fully demagnetize, and a fascinating thing would happen as you pulled it away from the magnet: it would cool down. Exactly as much as it heated up in bringing it close to the magnet.

Wacky, no?

Basically, you're on firmer ground in terms of thinking this would make a nifty refrigerator, based on the rule that it heats when placed in contact with a magnet and cools when removed from contact. You put a fan on the magnet to blow away the heat (through convection) when it's in contact with the magnet, cooling it back down to room temperature. Then, you pull it away and quickly place it in contact with your refrigeration chamber. Your magnet absorbs a little heat from the refrigerator, warms up a little, and you place it back in contact with the magnet and fan.
May 22, 2008
scott, you blogged about this! you totally saw that coming

May 22, 2008
IVIL asks --- [i wonder why you went down to 38 comments a day from approx 150?]

May I suggest that it could that people don't like to be rated?

BRAD K. = -3

Why? Their posts had nothing in them that would warrant a minus. Who the hell decides that these individuals should get a minus at all? But then, every time I have posted since this change, I don't remember getting a plus. Everything has been minus. Just because I'm paranoid doesn't mean that Scott didn't think this up to get rid of some of us. I say PENIS to you, Scott. When I wrote the f-bomb the other day, it came out as all apostrophes and pound signs, anyway. PENIS came out as PENIS, but then PENIS always does, doesn't it? So PENIS is alright, but !$%* isn't? Okay, I give. I will stop posting and just ride off into the sunset as it seems everyone would like. PENIS PENIS PENIS. There have that.

Rita Mae

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