Welcome to brain Stuff from how stuff works dot com where smart Happens. Him Marshall Brain with today's question, how do the new full body scanners at airports work? And this really is an interesting question because there's two parts to it. There's the actual technology of the scanners, but there's also the huge uproar they're causing right now, So we can look at both aspects of that and see
how they're converging right now. The thing you notice if you've been watching the news is that there's a huge uproar around these new full body scanners that are being deployed at airports around the United States right now. There are people loudly claiming that the t s A is handcuffing them to chairs for refusing to be scanned, for example, and the t s A responding that it never happened. There are videos showing little toddlers dreaming during pat downs.
There are calls for congressional oversight, passenger boycotts, acts of private protest t s A abolishment. Even in New Jersey there's claiming that they're going to stop the t s A, and in Orlando they claim that they're going to replace the t s A with private contractors, so there really
is a big debate going on right now. There are many reasons why people tend not to like these new full body scanning machines, but the two primary complaints are health concerns from X ray radiation and privacy concerns, both from being groped during pat downs if you opt out of the scan and from the possibility of scanned photos being distributed. Whether you love or hate the Transportation Safety
Administration and its mission, the mission is clear. The t s a's goal is to keep passengers from carrying weapons and explosives onto airplanes. We can generally agree as a society that this is a worthwhile goal. No one us to see a terrorist wearing a suicide bomb blow up and the airplane and kill three people in the air. One obvious way to carry the weapons on is in luggage and handbags. The other way is to attach them
to your body. The X ray machines that we use to scan luggage are generally considered to be safe and effective, so no one's really worrying about those. But when it comes to searching the bodies of passengers, the use of metal detectors and normal pat downs appears to have problems. First, metal detectors can't detect some explosives, which often don't contain much metal, and a normal pat down may not be very effective. Passengers wiggle and complain. Passengers are naturally reluctant
to have their personal areas explored by a stranger's hands. Therefore, the person doing the pat down may not be very thorough. And if certain parts of the body, for example, the genital areas or certain types of people for example toddlers, are deemed inappropriate for padding, then those obvious places to hide weapons. What is an alternative to full body scanners? One alternative would be to have passengers enter a private booth in which he or she would remove all clothing
and hand it to an agent. Then the clothing and the passengers naked body or photographs thereof would be examined. Then the passenger would redress and exit the screening area. This would be effective, but it has two problems. First, many, perhaps most, passengers would openly rebel, and second, it could really slow down the screening process, making it more expensive. There might also be problems with pornography and child pornography laws.
Instead of making everyone get naked in a booth. The t s A has instead deployed two types of screening machines that let passengers skip the undressing part. The machine undresses you by either using X rays or millimeter radio waves. The backscatter X ray technique is the one getting the most publicity at the moment. In this machine, visualize a beam of low power X rays, similar to a laser beam in dimensions, scanning across your body left or right,
top to bottom. The machine uses detectors to see how many of the X rays scatter off of each point of your body. Certain materials like clothing don't cause much scatter at all. Skin has a certain characteristic scattering effect, as do different metals and certain kinds of explosives. The machine paints an image of the back scattered results point by point, and an agent looking at that image can see things like metals, ceramics, and explosives attached to a
passenger's body. The image that comes back is basically an image of a naked human body. It's a strip search without the stripping. It's fast and efficient. So what's the problem. There are three? Actually, First, many people don't like the idea of having photos of their nake bodies taken by any means. In addition, there are a number of stories of abuse e g. You get attractive women being more
likely to be scanned or leaked images. Supposedly impossible, but obviously not since leaked images are on the Internet, and it doesn't help to have the kind of stuff happening. Second, because X rays involve ionizing radiation, many, perhaps most people have health concerns. All you have to do is look at the public reaction around any new nuclear power plant or the public acceptance of sunscreens to understand these concerns, even if the experts and the t s A say
the machines are safe. The third problem is the perception that it's much ado about nothing, that the t s A represents security theater rather than actual security. This idea first took root because the t s A has not traditionally been very proactive. A terrorist had to bring explosives in the soles of his shoes before the t s A scan shoes. A terrorist had to bring innocent looking liquids to mix a bomb in the air before liquids
were prohibited. Printer cartridges were not banned until explosives showed up in printer cartridges, and millions of people get onto subways every day without any screening at all, and that seems to work all right. In the case of the back scatter scanners, the t s A actually is being proactive. It is plugging a security hole before anyone exploits it. But in doing that, the t s A has met with significant resistance. And there's another problem that no one's
really discussing right now. A passenger who is striped search still has a currently undetectable way to bring in explosives. The passenger could swallow plastic explosives wrapped in rubber or plastic along with a detonator. The human stomach can hold a couple liters of food and is fairly resilient. One person was known to swallow seventy eight forks and spoons before having to see the doctor. There's no easy way right now to detect this approach short of medical X
rays or ultrasound. That leaves us with our current spectrum of choices. At one end of the spectrum, we could let passengers walk onto airplanes like we let them walk onto subway trains, zero security of any kind. At the other end of the spectrum, we could give naked passengers full body cat scans before every flight. Somewhere in the middle is a level of security that the majority of
passengers will willingly accept. Apparently, full body X rays scanners maybe a little beyond that limit at this moment in history. For moral this and thousands of other topics. Does that. House staff works dot Com and don't forget to check out the brain stuff blog on the house stuff works dot com home page. You can also follow brain Stuff on Facebook or Twitter at brain stuff hs W. The house stuff works dot Com iPhone app is coming sin get access to our content in a new way. Articles, videos,
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