The Physics of Sandman
LIANE HANSEN, host:
"Spider-Man 3" is the box-office champ of the year so far. One reason is the star turn of the villainous Sandman.
(Soundbite movie "Spider-Man 3")
Mr. TOBEY MAGUIRE (Actor): (As Spider-Man) Flint Marko.
HANSEN: Sandman's body is made of sand and he controls its density. He can pack the sand in his fist as hard as a rock or he can turn himself into the kind of sand you find on the beach. It makes him a tough target for a bullet or a punch.
Now, Sandman is not scientifically accurate, but James Kakalios says there is more to Sandman than special effects. Dr. Kakalios is a physics professor at the University of Minnesota and he's the author of "The Physics of Superheroes." Dr. Kakalios is at Minnesota Public Radio in Saint Paul.
Welcome to the program.
Dr. JAMES KAKALIOS (Physics Professor, University of Minnesota): Thank you for having me.
HANSEN: Okay. Outline those unique properties that Flint Marko aka Sandman is showing off in "Spider-Man 3."
Dr. KAKALIOS: Right. Well, sand is a fascinating system. It stacks like solid but can pour like a liquid, and by just changing the space in between the grains by as much as - as little as 10 percent, you can go from a light fluffy configuration, which makes it very difficult to hit and Spidy's spider-strength is basically useless as he punches at just a pile of sand or he can change the packing of the grains of sand to be as hard as rock and slugs Spidy and knock him out of an armored car across a construction site. So all of that that he does in the movies and he also does this in the comic books, perfectly accurate from a scientific point of view.
HANSEN: Okay. So sand. Isaac Newton is someone who explored it.
Dr. KAKALIOS: Absolutely. Isaac Newton taking up a conjecture by Kepler as to what would be the densest packing of spheres, three-dimensional spheres. Newton correctly calculated that the densest packing would still have about 26 percent open spaces, only 74 percent of the space in any given volume could be filled by spheres. So there's always been an interest in granuline materials from both a science point of view and a financial point of view.
If you look at ancient Mesopotamia, they sold grain by the basketful and you don't want to jostle it. You don't want to disturb it, because then the grains can rearrange themselves and they settle down and they have less volume. So now you have to add more if you're going to sell them a full basketful of grain.
Moreover, it was discovered that if you shake a mixture of, say, large and small sand, the larger grains would rise to the top. And this is called, in science, the Brazil Nut Problem, because when you open up a can of mixed nuts, you find that the larger nuts are on the top. Even if you put them on the bottom of the container of mixed nuts and then give it a bigger shake, up and down, you'll find that the larger nuts - even though you think, well gee, they're bigger, they're heavier, they should sink to the bottom - the large ones actually rise up to the top.
HANSEN: You all don't do this by rotating a can of nuts to see if the Brazil nuts get on top. You use computers, right? Computer imaging to figure this stuff out.
Dr. KAKALIOS: Well, we do both. Interestingly enough, I'm recently in communication with the vice president of visual effects of "Spider-Man 3" and it turns out that they're using the exact same computer programs and codes to simulate the effects of Flint Marko, Sandman in the movie, that we used in the laboratory or to simulate the properties of sand for our research papers.
HANSEN: This must be nirvana for you - the summer - with the movies coming up: "Fantastic Four." You've got whole new set of super heroes.
Dr. KAKALIOS: You know, I'm looking for - I've always been a "Fantastic Four" fan because I also like the fact that their leader, Reed Richards - Mr. Fantastic - in addition to having elastic powers, one of his other main strength is that he's one of the smartest men in the Marvel universe. And he always tends to outthink or outwit Dr. Doom or Galactus or what have you. So I'm looking forward to that because whenever they put an emphasis on creative problem solving, hey, that's what we do in the lab.
HANSEN: James Kakalios is a physics professor at the University of Minnesota and the author of "The Physics of Superheroes." He joined us from the studios of Minnesota Public Radio in Saint Paul. Thanks a lot.
Dr. KAKALIOS: Oh, it's a real pleasure. Thank you.
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