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If physicists are right, most of the matter in the universe is made up of exotic stuff you can't see, called dark matter.
Usually, people think of dark matter as existing only on the far edge of galaxies, posing such a deep, dark mystery that only the professionals can understand it. But that would be wrong on two counts: First, there's probably some dark matter zipping through you right now. Second, the mystery of dark matter is now explained in an education kit that has been designed for high-schoolers - and is freely available over the Web.
"The Mystery of Dark Matter," released last month by Canada's Perimeter Institute, is the first in a series of kits that will take on the big questions in physics, ranging from quantum mechanics to black holes. The Perimeter Explorations kits provide high-school science teachers with a DVD explaining the mysteries, as well as student worksheets and a teachers guide.
The education kits were created to respond to requests from teachers who have participated in the institute's seminars over the past few years, said John Matlock, director of external relations and outreach.
"The No. 1 request was for content that had 'hooks' in their curriculum, whether it was the math or the science ... but also addressed the cutting edge of science," Matlock told me. "They wanted concrete, complex, abstract ideas made visual, and they wanted to hear and see real-life researchers who are working on real problems."
Matlock said the dark-matter mystery was a good topic to kick off the series.
"It's a modern problem," he said. "This isn't your old Newtonian physics."
In the course of explaining the modern mystery, the DVD does gives students a healthy but relatively painless dose of that good old Newtonian physics as well as newfangled Einsteinian relativity. The equations for gravitational measurements vs. visual measurements solve themselves on the screen. (If only the math were that simple in real life!) You also see how gravitational lensing - a phenomenon explained by general relativity - has helped scientists map the unseen dark matter.
There's even a simple lab experiment to do - requiring a paper clip, a plastic tube, some metal washers hanging on a string, and maybe a little LED light if you want to get fancy. The experiment shows why the rotation rate of distant galaxy clusters led scientists to conclude that they were missing a whole lot of mass in their observations.
"It's actually quite dramatic when you do that in classes," Matlock said.
The kit doesn't exactly solve the mystery surrounding dark matter, but it does trace the different theories about its nature: Is dark matter nothing more than objects in outer space that don't emit light? Or cold neutrinos? The prevailing view is that at least some of it has to be more exotic - perhaps as-yet-undetected particles that permeate every part of our galaxy, including high-school physics classrooms.
Last year, CERN theoretical physicist John Ellis told me that there should be, on average, one particle of dark matter zipping through a one-liter bottle of water at any one time.
"However, this dark-matter particle is traveling quite fast," he explained. "It's traveling at some fraction of the velocity of light, so it doesn't stay inside the bottle. ... Most of the time, it would pass straight through the bottle without leaving any trace."
That part of the mystery could be addressed starting this year in the world's widest science lab, the Large Hadron Collider on the French-Swiss border. It's conceivable that one of the students swinging around those washers on a string will end up unraveling the dark-matter mystery at the LHC.
The Perimeter Institute's education kit is designed to be used as an optional supplement for senior high-school physics classes. The content, developed in cooperation with researchers around the world, was tested by about 100 teachers and 1,000 students who have come through the institute for seminars over the past 18 months.
Matlock said the final version was released just a month ago, and 1,000 of the kits have already gone out to schools, at no charge. The initial reaction has been "fantastic," he said.
"So far, it's off to a great start," Matlock said. "We think we've hit a real nerve here."
He expects the initial run of 2,500 kits to be exhausted by summer. "In theory, if each teacher were to use the kits twice, this could reach about 125,000 students in relatively short order," he said.
If those 2,500 kits run out, the Perimeter Institute will just do up another batch. Teachers can get the whole kit sent to them for free if they sign up, while non-teachers are free to download the video and the guide online.
The next kit on tap will tackle quantum physics, including the spooky phenomena of entanglement and teleportation. Matlock said the key to success will be to show how quantum mechanics enters into everyday applications such as laser scanners, CD players and super-secure data transmissions.
"As soon as the kids are turned on to that, you've got them pumped," Matlock said.
For more on the mystery, check out our brand-new Weird Science gallery as well as our dark-matter interactive. Are there other cosmic mysteries you'd love to learn about? Put them in the suggestion box by leaving a comment below.