February 28th, 2012
09:28 AM ET

The Ultimate Periodic Table

Theo Grey has a remarkable collection of pure elements, which he keeps in a giant, wooden periodic table. In this video clip, he shows off some of his most interesting specimens, and talks about how his collection got started. Grey is a co-founder of Wolfram Research and the author of The Elements, a wildly popular iPad app about the periodic table. He also writes a column about dangerous science experiments for Popular Science magazine.

Theodore Grey
The Elements
Periodic Table

This video was produced by the American Chemical Society.

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Fish scales may inspire body armor
Despite the piranha's sharp teeth, it can't break through the scales of the arapaima.
February 13th, 2012
11:12 AM ET

Fish scales may inspire body armor

A huge fish that is impervious to piranha attacks could become the inspiration for a new class of ultratough composite materials.

Its scales are so tough that piranha teeth crack when they chomp down onto them. Each scale is coated with a rock-hard mineral material, but they have soft cores made from strings of stretchy protein. The fish is called the arapaima, and it's native to Brazil.

“You often find this in nature, where you have something hard on the outside, but it rides on something softer that gives it toughness,”  Marc Meyers, a professor at the University of California, San Diego, said in a statement.

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Is this a clue to toenail evolution?
Paleontologist Jonathan Bloch holds the nail and skull of an ancient extinct primate, Notharctus tenebrosus.
January 24th, 2012
11:26 AM ET

Is this a clue to toenail evolution?

While sorting  through primate fossils at the American Museum of Natural History, Stephanie Maiolino and Douglas Boyer found an extraordinary specimen. Encased in a block of mud and rock was the fossilized foot of an extinct creature called a notharctus.

They sent the foot, still encased in mud, to their colleague Joe Groenke at Stony Brook University in Stony Brook, New York, and he did a CT scan. The foot bones were in good shape, and one of the toes looked unusual.

"It had a flattened tip, as you see in nailed-anthropoids, but the base of the claw showed that it would [be] projected up like a grooming claw and that it had weak muscle attachments, meaning the toe wasn't used for grabbing objects and locomotion like the other toes," Boyer explained.

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Revolutionizing sticky goo for tape, notes
Researchers say office tape could be reusable if it’s made with a substance called polydimethyl siloxane.
January 9th, 2012
12:28 PM ET

Revolutionizing sticky goo for tape, notes

New types of adhesives could be used to make remarkably reusable office tape, sticky notes or even bandages, according to chemical engineers at the Indian Institute of Technology in Kanpur. The new materials are almost as strong as normal adhesives, but they can be peeled off and stuck back onto an object repeatedly without losing much of their stickiness.

Peel back an ordinary piece of tape, and some of the sticky stuff will be left behind. Even worse, the used tape may be covered in gunk that won't come off. That's because most adhesives are tacky, gooey, viscous substances. They can be pulled off of their backing or ruined by flakes of paint and dust.

Researchers have come up with new adhesives designed to avoid those problems. They report their findings in the journal Langmuir, a publication of the American Chemical Society.

"There are two layers in this adhesive tape," explained Ashutosh Sharma, a chemical engineering professor who led the study. One of the layers is a "slimy goo core topped with a much thinner nonsticky elastic skin, which is easy to clean."

The thick layer of goo is what gives the new adhesive its stickiness, and the thin skin protects the goo from mixing with dirt or coming off of its backing.

Oddly enough, both the sticky goo and the nonstick elastic goo are made from the same chemical, a substance called polydimethyl siloxane, a rubbery polymer that is made from long chains of silicon and oxygen. The main difference between the two materials is that the thin skin has a lot of links between neighboring chains, which makes it more rubbery.

To find out just how reusable they are, graduate student Sandip Patil made some tape using the new adhesive. He attached it to a piece of glass and pulled it off of the glass repeatedly. It didn't leave any sticky residue behind, and it adhered to the glass almost as strongly as normal tape. If the tape got dirty, he could make it work again by cleaning the dirt off with another piece of tape.

In their journal study about the adhesives, Sharma and Patil say the new materials can be put into standard tape-making machines. So it would be easy for a tape company to start using it. The researchers also say they can fine-tune the stickiness of the tape by increasing or decreasing the thickness of the elastic layer.

Since these adhesives have two distinct layers, they're more complicated than the single-layer goo that you would find in a standard roll of office tape. But they're not nearly as complicated as some of the sticky things that nature has made. Gecko feet and insect toes are far more complex. By mimicking those natural stickers, engineers may someday make even better glues.

Diamonds 'entangled' in physics feat
A beam of light was split between two diamonds, then recombined before heading toward an ultra-sensitive detector.
December 7th, 2011
10:09 AM ET

Diamonds 'entangled' in physics feat

By zapping diamonds with an enormous number of laser beam pulses, physics researchers have created several cases of what Einstein called "spooky action at a distance."

A team of scientists showed that two diamonds can entangle with one another, meaning that vibrations in one of the crystals share an invisible, long-range connection with vibrations in the other crystal.

"We have been able to demonstrate that even everyday objects can exhibit some of the strange, counterintuitive behavior of quantum physics," said University of Oxford professor Ian Walmsley, who led the study, published recently in the journal Science.

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Diamond sandwich makes metallic hydrogen
Researchers compressed hydrogen between two diamonds inside this device, known as a diamond anvil cell.
November 17th, 2011
11:54 AM ET

Diamond sandwich makes metallic hydrogen

Hydrogen, the most abundant element in the universe, is commonly found as a clear gas. But squish some hydrogen with an enormous amount of pressure and it will turn into a metal, according to researchers at the Max Planck Institute for Chemistry in Mainz, Germany.

Chemists Mikhail Eremets and Ivan Troyan sandwiched hydrogen between two diamonds and compressed it while carefully monitoring the atoms with a set of lasers and electrodes. To apply the pressure, they used a diamond anvil, which is similar to the machines that crush coal with so much force that it turns into artificial diamonds.

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