Science to the rescue: on September 11, 2001 two hijacked planes crashed into New York City's World Trade Center, collapsing the 110-story Twin Towers and claiming more than 5,000 lives. The disaster site became known as Ground Zero. (Special Report).

At Ground Zero, elite rescue teams sprang into action with help from "man's best friend" and cutting-edge technology.

1. Every Urban Search and Rescue Team (USAR) has 62 trained specialists, 4 dogs, and 16,000 pieces of equipment. But before workers climb onto the wreckage, search and rescue dogs sniff the rubble for human scent. How can dogs smell people buried deep in debris? With intensive training and 220 million keen olfactory receptors (scent cells)--40 times that of a human nose.

When a dog inhales, the alar fold (bulb in the nostril) opens; air rushes up the nasal cavity and odors bombard scent receptor cells. The scent cells carry chemical signals to the dog's olfactory bulb (part of brain that analyzes odors). If the smell is human, the dog barks to alert its handler. Its reward: praise and play.

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2. What if the terrain is too risky for dogs? Send in the newest high-tech USAR tool: remote-controlled marsupial robots. The shoebox-size tanks are called marsupials because, like the pouched mammals, robot "mothers" carry a "baby bot" in a pouch-like cavity. "They're like small tanks with cameras on them," says James Hannigan, director of the New York State Association of Fire Chiefs. "They run the robots in crevices where a human can't get to and in very unstable places."

When the mother reaches a narrow crevice and ejects the flexible baby bot, the baby squeezes into the rubble and uses audio sensors, cameras, and digital thermometers to explore. Both robots feature artificial intelligence, high-level computer programming that gives them an ability to "think" using specialized sensors and software. If a baby bot's gadgetry senses a human, it signals its mother. She then beams images to a TV monitor, letting rescuers see through the baby robot's camera eyes.

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3. To hear survivors, rescuers rely on Life Detector, a sensitive listening device. Rescuers strategically place up to six sturdy acoustic (sound) sensors amid the ruins. If a victim taps on a piece of rubble, the vibrations travel along a slab of material until 8-inch-long sensors detect the vibrations and convert them into audio signals that a rescuer wearing headphones can hear.

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4. In the end, rescuers dig into wreckage to save lives. "It takes a lot of training," Hannigan says. "But as intense as USAR training is, nothing can prepare you for a disaster like this."

Penetrating rubble is slow and dangerous. "You can't cut through the debris with heavy equipment," says Bruce Baughman of the Federal Emergency Management Agency. So workers gingerly shovel into the twisted steel, scooping rubble into 5-gallon buckets and passing them down a 200-foot human chain. When workers hit a void, they snake in a fiber-optic probe (thin glass or plastic tubes) that transmits black-and-white images to a monitor strapped to an operator's chest. If he sees a person, a rescuer worms into the ruins. Does he fear for his own life? "You don't think about yourself. You think about the person trying to save," says Hannigan. "You're fighting time."

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Cross-Curricular Connection

History: Research the history of the skyscraper. List the five tallest skyscrapers in the world, noting their location and when they were built.

Did You Know?

* Rescue teams scrawl graffiti on surfaces within the ruins of the World Trade Center to mark the areas they've searched. They record their team identification number, departure time and date, hazards, and number of victims found.

* Disaster-area workers use air horns to communicate. For example, if the debris in a particular area is unstable and potentially dangerous, three one-second blasts mean "evacuate the area." If the wreckage area is safe, a single three-second blast means "all quiet." One long blast followed by a short blast means "resume operations."

National Science Education Standards 

Grades 5-8: risks and benefits * regulation and behavior

Grades 9-12: natural and human-induced hazards * the behavior of organisms

Resources

"Agile in a Crisis, Robots Show Their Mettle," by Jennifer 8. Lee, The New York Times, Sept. 27, 2001

Federal Emergency Management Agency's Canine Heroes Web site: www.fema.gov/kids/games/heroes

Name: --

page 7 Special News Report: Science to the Rescue

Directions: Answer the following questions in complete sentences.

1. Explain what search-and-rescue dogs do. What physiological trait makes dogs good at their job?

2. Describe the "bathtub" beneath the World Trade Center. Why is it an important engineering feat?