Thursday, November 20, 2014

Super Geckos!

What would it be like to walk up a wall or to hang from a ceiling? What if you could go out and buy super-powers at your local Walmart? A group of scientists at Stanford University in California have made it possible for a human being to climb the side of a skyscraper with specially designed hand pads.

People have tried to make climbing pads from suction cups or adhesives. They've failed, often painfully. How did the scientists at Stanford succeed? They decided to study one of nature’s best climbers: the gecko.

Geckos are nature’s most spectacular climbers. They can stick to any surface, but they can also un-stick at will. Their foot pads don’t lose stickiness over time, and a very small area can support a lot of weight. The scientists at Stanford realized that if humans were ever going to imitate superheroes, they’d have to imitate nature’s superhero first.

To learn how geckos stick to walls, biologists studied their feet under electron microscopes. It turns out that a gecko’s stickiness happens on the nano-scale .  The pads on a gecko’s feet are covered with tiny spiked made of beta-keratin, the same material that a bird’s beak is made of. Each spike is only 10 micrometers across. That’s about half the diameter of the finest human hair.  The ends of each spike split into a bundle of even smaller spikes that can only be measured on the nanoscale.

When these smaller spikes come into contact with a surface, they take advantage of the Van der Waal forces that attract molecules to each other. The force on any one nano-spike is miniscule. However, each gecko foot has so many nano-spikes that it can hold a kilogram to the ceiling! That means an entire gecko could support over 16 pounds.

The scientists at Stanford created a material with similar properties to the gecko’s foot.  First, they used it to create small climbing robots. These tiny mechanical geckos could be useful for surveillance, building, or conducting maintenance in harsh environments like space or under the sea.
Then, they scaled their product up and tested it on humans. 

Currently, the program is being funded by the Defense Advanced Research Products Association (DARPA).  That means that, in the short term, these gecko-pads are probably going to be reserved for the military and the space program. But don’t despair – they’ll eventually reach the public, just like silicone potholders and Velcro shoes!

So, what do cool climbing pads have to do with your biology class?  Well, when you have to look through a microscope and draw what you see, you’re doing what these scientists did to figure out how geckos climb. And when you’re learning about proteins and their structures you’re getting some of the basics of materials science. 

Learning about how biological materials work helps us develop artificial materials that share some of the same amazing properties.  So, the next time you’re studying something in biology class, think “How can I turn this into a super-power?”

Tuesday, November 18, 2014

Moai Movers

Courtesy of Wikimedia Commons and Dpirrman

My kids just watched a great episode of NOVA where scientists studied the statues of Easter Island and tried to figure out how they were moved into place. Before you get too overwhelmed by my children's interest in Polynesian archeology, I feel the need to point out that they developed their interest in Moai Heads because my husband plays Sam and Max.

Anyway, the episode could be fun and useful viewing for math and science students. What does archeology have to do with math and science, you ask? Well, to study how the Moai heads moved, the archeologists had to master concepts like center of gravity, mass, friction, normal force, work, and vectors.

Do you like learning about ancient cultures and figuring out how they did things? Then you probably want to get a good grounding in basic math and physics.

Dark Matters: Using GPS to Find the Unfindable

Astrophysicists have a major problem. They’ve calculated the mass of the universe. They know how much stuff is supposed to be out there. But they can only find about 5% of it. The rest of the universe is composed of something that they call “Dark Matter” and “Dark Energy.” They know its out there because they can see how it bends the light coming to earth from distant stars. But they can’t directly detect it. It’s invisible to our sensors. If we look right at it, it disappears. So how can they find the dark matter that they know is there?

In a way, their problem is similar to one that an elderly woman I know has. Her vision isn’t what it used to be. She can no longer see black, blue, or red cars when she’s driving. “It’s pretty lucky that everyone drives white and silver cars these days,” she reminds me.  Both of my cars are maroon. She can’t see us, but she’ll find out we exist when she crashes into us.

Two scientists have come up with a creative new way to crash into dark matter so that we can ‘see’ it. They’re going to analyze data from the existing GPS satellite system. 

Every GPS satellite is equipped with an atomic clock. Atomic clocks tell time based on how frequently an element absorbs microwave radiation. Theoretically, every clock should be in sync, but the satellite clocks do fall out of sync as the circle the earth. Scientists know how  big these discrepancies should be. If they find a clock that’s fallen further out of sync than it should have, they’ll know that the GPS satellite has encountered dark matter.

The scientists tracking dark matter have an alternate theory about what it might be. Currently, most scientists think that dark matter is composed of actual particles. However, these particles don’t react to electromagnetic radiation like light, x-rays, or radio waves, so we can’t see them.  The scientists analyzing GPS data think that dark matter may not actually be ‘matter’ at all, but lumps, tears, and other imperfections in the very fabric of the space time continuum.  Sounds more like Star Trek than science class, doesn’t it?  It’s pretty cool.

So, what does this have to do with what you’re learning in class? Well GPS functions using basic properties of circles. Without coordinate geometry, there would be no GPS, and therefore no dark-matter detector. Plus, atomic clocks work based on microwaves, which we model using sine and cosine functions.   Math. You can’t escape it. But if you learn it, you might get to do really cool things some day.