Regarding magnetic “silverware” in restaurants from NPR’s Car talk (week of 9/22)

PUZZLER: A Magnetizing Dinner Chez Magliozzi
Over dinner, Ray’s wife notices that her knife and fork are stuck to each other, her knife was magnetized. Ray’s son’s knife was magnetized too, but the polarity was the reverse of her’s. Ray’s niece offers an explanation. What was her theory?

RAY: It wasn’t a family dinner at home, we were at a restaurant. And restaurants have such large losses of silverware, that they throw into their trash receptacle an enormous magnet so that when silverware is mistakenly thrown into the trash can, the forks, spoons and knives all get stuck to this magnet, and if it’s on there long enough it gets pretty magnetized.

TOM: Wow.

RAY: So that’s how it happened. So the next time you’re at a restaurant you can do a little parlor trick. Find a utensil that’s magnetized, and you can pick up somebody’s keys and drop their keys in their soup.

There was a brief discussion of this on a teachers’ listserv I’m on, where one teacher asked, but isn’t restaurant flatware stainless steel, and isn’t stainless steel nonmagnetic?

Another informed us:

Some stainless steel is not magnet, but not all. The kind of steel in cutlery is usually magnetic. Check out this link.

Several companies make magnetic catchers. For example, check out this link.


We heard a delightful plenary last night from Michio Kaku, the co-founder of string theory and a great popularizer of science. He’s written a ton of books including one of the same name as this talk. He’s also got an upcoming series of episodes on the Science channel, starting August 10th, 3 Sundays in a row.

He began with a joke. A priest, a lawyer, and a physicist all face the guillotine. The priest is up for the chopping block first, and they ask him, “Do you have any last words?” Yes, says the priest, “Please, God, by your holy spirit, set me free.” They put him under the guillotine and, lo and behold, the blade stops just before it reaches is neck. “God has spoken!” says the magistrate, and they set the priest free. Next up is the lawyer, and he’s asked if he has any last words. “Yes,” he says, “the spirit of justice will set me free!” They let the blade fall, and it stops just short of his neck. “The spirit of justice has spoken!” cries the magistrate, and they set the lawyer free. Last up is the physicist. He’s asked for his last words. “I know little about God,” says the physicist, “and even less about justice. But I do know one thing. If you look up, you’ll see that the rope is stuck on the pulley. If you set it free, that blade should come down real good.” So, they did that, and indeed, the guillotine worked just fine for the physicist. The moral of the story? Physicists should learn when to keep their mouths shut.

That’s been true throughout history, says Kaku. Lots of physicists have looked foolish by, for instance, declaring certain things to be impossible. Lord Kelvin, for example, said that:

  • “Heavier than air” craft were impossible
  • X-rays were probably a hoax
  • The earth couldn’t possibly be older than a few million years old.

That last is interesting — he did the calculation based on a time-rate of cooling of the molten core of the earth and found it would be stone cold by now if it were older than a few million years. But, he didn’t know about the nuclear force at that point, and thus the nuclear decay which fuels the heat of the earth. The lesson learned here is that you have to understand all the laws of physics in order to make predictions about what is possible or not. New things are discovered all the time, and in the time of Lord Kelvin we didn’t know yet about quantum mechanics and relativity, to name a few, which are essential for understanding how the world works.

Another thing that was thought impossible was rocketry. The NY Times denounced Robert Godard (the father of modern rocketry) because rockets couldn’t possibly move in outer space. In outer space, they said, there is no air to push against. (Now, that’s true, but remember Newton’s 3rd Law — the rocket expels stuff out the back so the whole rocket has to move forward).

And of course, there are Arthur C. Clarke’s Three Laws:

  1. When a distinguished but elderly scientist states that something is possible, he is almost certainly right. When he states that something is impossible, he is very probably wrong.
  2. The only way of discovering the limits of the possible is to venture a little way past them into the impossible.
  3. Any sufficiently advanced technology is indistinguishable from magic.

On the other hand, there are some things that are really likely to be impossible, because they violate all the known laws of physics, like perpetual motion machines and precognition. See my previous post on crackpot science for some discussion of why folks like to think they’ve disproven those juicy laws like relativity.

But there are some things that we used to think are impossible we’re likely to see in the next few decades or, perhaps, the next few milennia. For example….


We used to say invisibility was impossible because light can’t wrap around an object and come together on the other side, like water can. If you’re downstream from a boulder, the presence of the boulder is “invisible” to you because the water wraps around the boulder. Another way of saying that is that light can’t bend with an index of refraction less than zero. But, now we know that’s not true, using stuff called “meta-materials”, which are artificially engineered, we can indeed bend light. This has been done with microwave frequency light (where the wavelength is about the thickness of your thumb) and with red and blue light. It’s done by putting impurities into the material that “kick” the “crest” of the wave a little bit, so that overall the whole direction of the wave gets changes in a way that we wouldn’t have predicted before these meta materials with negative index of refraction were created. This is just proof-of-concept right now. In order to make something completely invisible, we’d need 3 types of meta materials for each color of visible light. Plus, not only can people outside the invisibility “cloak” not see in, but those inside the cloak can’t see out, so you’d essentially need to cut two eyeholes to see out. Read more about how invisibility works.


So, it’s impossible to dissolve and reappear, right? Well, not if you’re a subatomic particle. They’ve now “teleported” particles a record of about 100 miles, between two Canary islands, and they’re asking for permission to teleport a particle to the moon. This uses the principle of quantum entanglement, which basically says that you can “entangle” two particles so that when one particle changes, the other one changes too. So it’s not the original particle that was sent between the two islands, but rather the information contained in that particle (it’s “quantum state”). Read more about it.

So, the question arises — if I were to be teleported, and it’s the information in the atoms that make up “me” (and not the atoms themselves) that are transported, then what does it mean to be “me”? Does the soul consist of the quantum state of your particles? If you have to be destroyed in order to be teleported, who would sign up? Well, we’re certainly not at the point of being able to teleport people, but perhaps in 10 years or so we can teleport an atom or even a molecule.

Death Stars

Is it possible to vaporize an entire planet? Could we have a portable source of power for a ray gun powerful enough to do that? A decade ago, people shook their heads, though certainly there’s no upper limit to the energy of an H-bomb, it just doesn’t seem feasible to direct all that energy at a planet in a thin beam. But there is one thing that occurs in nature that fires a huge amount of energy in a thin beam and could destroy a planet — gamma ray bursters. These are huge emissions of power from stars as they collapse to form black holes. It turns out there’s one candidate star which could feasibly maybe possibly turn into a gamma ray burst — WR104. It’s 8000 light years away. Who knows, maybe it detonated 5000 years ago and we just don’t know it yet? The chances are, of course, that it won’t.

Telepathy and mind reading

According to Kaku’s definition, this has already happened! A project called BrainGate has created a direct connection between the brain of a stroke victim and a laptop. With a little practice, the stroke victim can learn to control the computer, including surfing the web, sending email, and playing video games, just by thinking about it! This certainly seems to fit the definition of psychokinesis, though it’s aided by artificial means. And mind reading? We can scan people’s brains using MRI machines and, while we can’t tell just what they’re thinking, we can tell with 98% accuracy whether they’re lying. When you tell a lie, your brain lights up like a Christmas tree (at least on the MRI scan).


It’s been hard to ignore the progress made in terms of semi-intelligent and humanoid robots recently. The most advanced humanoid robot is Asimo in Japan. Its reactions are pre-programmed, but the amazing thing is that it can walk and move like a human — no small feat! There’s a reason why most robots roll around instead of walking. It took Honda 20 years to get it to move like a human. For those of us with a little less money (but still doing pretty well) there is of course the Roomba — the robot vacuum cleaner. We tend to anthropomorphize these robotic “creatures”. He found his wife clucking with some sympathy for their Roomba, saying they should ‘let the poor robot rest.’ There is also the (very cute) Ibo, the pet robotic dog.

Yet for all these advances, Asimo is still about as smart as a cockroach. A retarded cockroach. The rovers on Mars take a full day to recognize a rock, says Kaku. A cockroach does better than that.

See Kaku’s book on the Physics of the Impossible here.

I just read this neat little gem in The Physics Teacher. Take a bunch of coffee stirrers (the kind that look like round straws for wee folke) and set them into a box so they’re all upright (all the little holes are looking up at you). Jiggle them and pack them tightly so that they seal flat against the side of the box with no “holes”. Then go somewhere that has a lot of loud ambient noise (I’m imagining the Exploratorium on a busy day), and put the open end of the straws against your ear.

According to The Weird Project, you’ll feel as if:

  • the air pressure is falling
  • invisible pillows are drifting around your head
  • your ears are about to pop
  • you are going deaf
  • your head is changing size
  • the size of the room is shrinking
  • you are about to faint
  • In other words, what happens is that part of the background sound goes away. Apparently when it works right, the effect is “very creepy.”

    What happens is that certain frequency bands (eg., certain pitches of sound) are attenuated (read, “partially blocked”) by the straws. The article in the Physics Teacher describes how to use a function generator and a speaker to determine which set of frequencies are most affected. They found that for 13.3 cm round stirrers, the sound level drops off at 660 Hz (I think that’s a high “A”) and again at 2000-3200 Hz. You can get a rough idea for the pitches of those sounds here.

    If you’re curious about this, definitely check out The Weird Project, it’s got a lot of good information on it.

    The World’s Fair blog just published a post highlighting a study from 1946 — Scientific Analysis Simplifies a Housewife’s Work. They used motion-tracking to analyze the most movements leading to the most efficient method for making a bed.

    In a similar vein, check out this “Good Wife’s Guide” from Housekeeping Monthly 1955.
    I originally thought this was a spoof, but a while after I had posted it on my website, I got this email:

    Greetings Stephanie,
    Thought you might like to know that “The Good Wife’s Guide” is NOT a spoof. About three years ago, I bought a handful of old magazines at a garage sale, one of which was “Housekeeping Monthly”, May 13, 1955. “The Guide” is/was indeed in there.

    If ya Google Image “The Good Wife’s Guide”, a number of the images have some lines faintly highlited with yellow, and the last line, in the RH column, has a squiggly circle drawn around it. That is my highliting, and my squiggly.

    The tragedy here is that in the process of trying to get rid of some clutter, I tossed the magazine. Been kicking myself ever since. Learned my lesson tho, ..
    Never, Ever, Throw ANYTHING Away!
    The attachment is a scan of a real ad, on a real magazine, dreamed up by un-real minds.

    So, anyhooo .. take care out there. I wish you Peace
    later daze,
    – bryan

    Crossposted on the World’s Fair

    check out this item from Science Daily…

    Humans have Ten Times More Bacterial Than Human Cells: How do Microbial Communities Affect Human Health?

    ScienceDaily -Jun. 5, 2008 — The number of bacteria living within the body of the average healthy adult human are estimated to outnumber human cells 10 to 1. Changes in these microbial communities may be responsible for digestive disorders, skin diseases, gum disease and even obesity. Despite their vital imporance in human health and disease, these communities residing within us remain largely unstudied and a concerted research effort needs to be made to better understand them, say researchers June 3 at the 108th General Meeting of the American Society for Microbiology in Boston.

    This is interesting in its own right, but also gives me a chance to point you to my favorite Krulwich on Science episode. Don’t know Krulwich on Science? Check it out. They’re only about 5-10 minutes long and some of the best-produced and entertaining science stories on radio (aside from RadioLab).

    So, one of my favorite Krulwich episodes (just 4 minutes of your time!) asks, so, who are we if we’re just microbe hotels? What constitutes you?

    Bacteria Outnumber Cells in Human Body

    July 1, 2006 · The human body contains 20 times more microbes than it does cells. In fact, a visitor from outer space might think the human race is just one big chain of microbe hotels.

    I’ve always been sort of fascinated by synthesia. A brain with a predilection to mix colors and letters and days and feelings and smells sounds kinda trippy. I’ve always thought (and I think I may have read somewhere) that it seems like a very rich way to experience life. I mean, confusion is orange? I don’t even have a way to relate to what that means, except through certain experiences from my college days. A recent web article writes about synthesia and some current theories (they still don’t really know what causes it). One interesting theory

    All of us are able to perceive the world as a unified whole because there is a complex interaction between the senses in the brain, the thinking goes. Ordinarily, these interconnections are not explicitly experienced, but in the brains of synesthetes, “those connections are ‘unmasked’ and can enter conscious awareness,” said Megan Steven, a neuroscientist at Beth Israel Deaconess Medical Center.

    Because this unmasking theory relies on neural connections everyone has, it may explain why certain drugs, like LSD or mescaline, can induce synesthesia in some individuals.

    One thing I’m curious about is how different (and how similar) the experiences of different “synthetes” is. The article mentions this a little bit. For example, a lot of synthetes associate colors with letters. But for some, they see the color in their minds’ eye. Others see the color sort of painted onto the physical letter. One synthete responded via a comment to the article above that the colors he sees associated with letters are completely different from those for others.

    One synthete writes:

    Not only do the colors vary from person to person, but the associations too. I see not only colors for letters and numbers, but gender too, which isn’t something I’ve seen discussed in articles like these. The letter “A” is not only red for me, but also very strongly female. Also, I see the year as a kind of pie chart around me (its orientation is synchronous), and numbers, especially the first 10 integers, have a very particular spacial position.

    And another replies:

    For me the colour is only the start – there’s a whole complex series of moods and associations that follow on from the first ‘hit’ of colour. This is particularly strong with peoples names.
    An additional observation – often the colour of the word id bizarrely out of whack with the real colour of the object. So, for me, ‘tree’ has no trace of green or brown or any other ‘tree’ colour – it’s a soft grey, fading to creamy yellow at the end.

    Interesting stuff, but hard (though not impossible) to study, being based on subjective experience.

    polar-bear.jpgThe answer seems to be yes! Even though polar bears are white, their hair is actually colorless. I found this out by looking at a great site, Everyday Mysteries, run by the Library of Congress. You can browse tons of questions, and their interesting science answers, compiled by the expert reference librarians at the Library of Congress. Aren’t librarians great?

    Here’s a link to the polar bear posting itself. The reason we can’t see through the “transparent” hair directly to the polar bear’s skin (eek! naked polar bear!) is that the hairs are hollow. The air inside the hollow space in the hair bounces the white light from the air back to our eye, sort of like millions of tiny mirrors tilted at tons of different angles. The result is that we see a white bear.

    In that same LOC posting is an interesting tidbit — bears at some zoos were turning green! Why? There was algae growing inside the hairs… so those hollow spaces weren’t reflecting white light anymore, but green light. How embarrassing for the poor polar bear.

    Note that polar bear hair is NOT a fiber optic. You can see my earlier posting about that.