The Most Dangerous Female Sport: Cheerleading

Cheerleading safety efforts have led to modest reductions in the number of serious injuries in recent years, according to a new report about college and high school sports and cheerleading mishaps.

But cheerleading caused more serious and deadly injuries by far than other female sports during the study period.

Researchers have long known how dangerous cheerleading is, but records were poorly kept until recently. An update to the record-keeping system last year found that between 1982 and 2007, there were 103 fatal, disabling or serious injuries recorded among female high school athletes, with the vast majority (67) occurring in cheerleading. The next most dangerous sports: gymnastics (nine such injuries) and track (seven).

Today, the National Center for Catastrophic Sports Injury Research at the University of North Carolina at Chapel Hill released its 26th annual report on the topic. The latest figures are from the 2007-2008 academic year for college and high school sports, male and female. The report defines catastrophic injuries as any severe or fatal injury incurred during participation in the sport.

The new numbers are for the 26-year period from the fall of 1982 through the spring of 2008:

There were 1,116 direct catastrophic injuries in high school (905) and college sports (211).

High school sports were associated with 152 fatalities, 379 non-fatal injuries and 374 serious injuries. College sports accounted for 22 fatalities, 63 non-fatal injuries and 126 serious injuries.

Cheerleading accounted for 65.2 percent of high school and 70.5 percent of college catastrophic injuries among all female sports.

The number of cheerleading injuries fell slightly in the 2007-08 academic year.

"Progress has been slow, but there has been an increased emphasis on cheerleading safety," said the study's author Frederick O. Mueller. "Continued data collection on all types of cheerleading injuries will hopefully show that these safety measures are working to reduce injuries."

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The Strange Ingredients in Fireworks

Fireworks for the 4th of July are all about light, color and sound. But inside, there are some bizarre ingredients, from aluminum to Vaseline and even the stuff of rat poison.

An ancient mix of black powder, essentially gunpowder little changed from its invention in China a millennia ago, gets each rocket in the air by creating pressure in gas trapped in a tube, or mortar.

Two fuses are lit at once: one to ignite the black powder, and another that burns slower, creating a well-timed explosion high in the sky.

The shells of commercial fireworks contain a powdery concoction of chemicals that produce the bangs and the whistles, as well as the pretty effects. Tubes, hollow spheres, and paper wrappings work as barriers to compartmentalize the effects. More complicated shells are divided into even more sections to control the timing of secondary explosions.

Big booms and whistles come from flash powder. Once used for flashes in photography, it is a combination of fuel-like metal and a chemical that feeds oxygen to fire up the fuel. Different combinations of metals and oxides produce a whole array of sounds.

While ancient Greeks and Romans used bismuth in their beauty care products and coins, chemists add bismuth trioxide to the flash powder to get that crackling sound, dubbed "dragon eggs." Ear-splitting whistles take four ingredients, including a food preservative and Vaseline.

The variety of color in a fireworks show depends on the mix of metals.

* Copper produces blue sparks.
* A mix of strontium salts, lithium salts and other stuff makes red.
* Aluminum and titanium put the white stars in an aerial flag.
* Barium, also used in rat poison and glass making, makes green.
* Calcium burns orange and sodium, yellow.

In recent years, chemists have worked to develop more environmentally friendly fireworks, in part because one ingredient, perchlorate, was found in higher than normal concentrations in a lake where fireworks were shot off, and the chemical is known to cause thyroid problems in humans.

Meanwhile, to light up a red, white, and blue flag, chemists can lay out the emblem's design on wax paper. The pattern you see up in the air, whether it's a smiley face or a bow tie, mirrors the arrangement of the metals in the shell.

Because the flag, or any other pattern, shoots out from the shell as a two-dimensional image, people watching the show from different angles can't always tell what they're looking at. To make sure everyone has a good view, pyrotechnists tend to send duplicates into the sky at the same time.

You can see fireworks before you hear them because light travels faster than sound.

Source: LiveScience

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The World's Smallest Robot

Researchers have built an inchworm-like robot so small you need a microscope just to see it. In fact about 200 hundred of them could line up and do the conga across a plain M&M. The tiny bot measures about 60 micrometers wide (about the width of a human hair) by 250 micrometers long, making it the smallest untethered, controllable microrobot ever. "It's tens of times smaller in length, and thousands of times smaller in mass than previous untethered microrobots that are controllable," said designer Bruce Donald of Dartmouth University. "When we say ‘controllable,' it means it's like a car; you can steer it anywhere on a flat surface, and drive it wherever you want to go. It doesn't drive on wheels, but crawls like a silicon inchworm, making tens of thousands of 10-nanometer steps every second. It turns by putting a silicon 'foot' out and pivoting like a motorcyclist skidding around a tight turn."

Because it makes use of this innovative bending movement and is untethered, it can move freely across a surface without the wires or rails that restricted the mobility of previously developed microrobots. The caterpillar strategy also helped the researchers avoid a common problem in microrobotics. "Machines this small tend to stick to everything they touch, the way sand sticks to your feet after a day at the beach," said Craig McGray of the National Institute of Standards and Technology. "So we built these microrobots without any wheels or hinged joints, which must slide smoothly on their bearings. Instead, these robots move by bending their bodies like caterpillars. At very small scales, this machine is surprisingly fast." To get around, the robot makes use of two independent microactuators – the robot's "muscles." One is for forward motion and the other for turning. It doesn't have pre-programmed directions. Instead, it reacts to electric changes in the grid of electrodes it moves on. This grid also supplies the microrobot with the power needed to make these movements.

This microrobot and similar versions that could be developed might eventually ensure information security, inspect and make repairs to integrated circuits, explore hazardous environments, or even manipulate human cells or tissues.

Source: LiveScience

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