Speaker 1: Welcome to brain Stuff from how stuff works dot com
Speaker 1: where smart Happens. Him Marshall Brain with today's question, how
Speaker 1: do the new full body scanners at airports work? And
Speaker 1: this really is an interesting question because there's two parts
Speaker 1: to it. There's the actual technology of the scanners, but
Speaker 1: there's also the huge uproar they're causing right now, So
Speaker 1: we can look at both aspects of that and see
Speaker 1: how they're converging right now. The thing you notice if
Speaker 1: you've been watching the news is that there's a huge
Speaker 1: uproar around these new full body scanners that are being
Speaker 1: deployed at airports around the United States right now. There
Speaker 1: are people loudly claiming that the t s A is
Speaker 1: handcuffing them to chairs for refusing to be scanned, for example,
Speaker 1: and the t s A responding that it never happened.
Speaker 1: There are videos showing little toddlers dreaming during pat downs.
Speaker 1: There are calls for congressional oversight, passenger boycotts, acts of
Speaker 1: private protest t s A abolishment. Even in New Jersey
Speaker 1: there's claiming that they're going to stop the t s A,
Speaker 1: and in Orlando they claim that they're going to replace
Speaker 1: the t s A with private contractors, so there really
Speaker 1: is a big debate going on right now. There are
Speaker 1: many reasons why people tend not to like these new
Speaker 1: full body scanning machines, but the two primary complaints are
Speaker 1: health concerns from X ray radiation and privacy concerns, both
Speaker 1: from being groped during pat downs if you opt out
Speaker 1: of the scan and from the possibility of scanned photos
Speaker 1: being distributed. Whether you love or hate the Transportation Safety
Speaker 1: Administration and its mission, the mission is clear. The t
Speaker 1: s a's goal is to keep passengers from carrying weapons
Speaker 1: and explosives onto airplanes. We can generally agree as a
Speaker 1: society that this is a worthwhile goal. No one us
Speaker 1: to see a terrorist wearing a suicide bomb blow up
Speaker 1: and the airplane and kill three people in the air.
Speaker 1: One obvious way to carry the weapons on is in
Speaker 1: luggage and handbags. The other way is to attach them
Speaker 1: to your body. The X ray machines that we use
Speaker 1: to scan luggage are generally considered to be safe and effective,
Speaker 1: so no one's really worrying about those. But when it
Speaker 1: comes to searching the bodies of passengers, the use of
Speaker 1: metal detectors and normal pat downs appears to have problems. First,
Speaker 1: metal detectors can't detect some explosives, which often don't contain
Speaker 1: much metal, and a normal pat down may not be
Speaker 1: very effective. Passengers wiggle and complain. Passengers are naturally reluctant
Speaker 1: to have their personal areas explored by a stranger's hands. Therefore,
Speaker 1: the person doing the pat down may not be very thorough.
Speaker 1: And if certain parts of the body, for example, the
Speaker 1: genital areas or certain types of people for example toddlers,
Speaker 1: are deemed inappropriate for padding, then those obvious places to
Speaker 1: hide weapons. What is an alternative to full body scanners?
Speaker 1: One alternative would be to have passengers enter a private
Speaker 1: booth in which he or she would remove all clothing
Speaker 1: and hand it to an agent. Then the clothing and
Speaker 1: the passengers naked body or photographs thereof would be examined.
Speaker 1: Then the passenger would redress and exit the screening area.
Speaker 1: This would be effective, but it has two problems. First, many,
Speaker 1: perhaps most, passengers would openly rebel, and second, it could
Speaker 1: really slow down the screening process, making it more expensive.
Speaker 1: There might also be problems with pornography and child pornography laws.
Speaker 1: Instead of making everyone get naked in a booth. The
Speaker 1: t s A has instead deployed two types of screening
Speaker 1: machines that let passengers skip the undressing part. The machine
Speaker 1: undresses you by either using X rays or millimeter radio waves.
Speaker 1: The backscatter X ray technique is the one getting the
Speaker 1: most publicity at the moment. In this machine, visualize a
Speaker 1: beam of low power X rays, similar to a laser
Speaker 1: beam in dimensions, scanning across your body left or right,
Speaker 1: top to bottom. The machine uses detectors to see how
Speaker 1: many of the X rays scatter off of each point
Speaker 1: of your body. Certain materials like clothing don't cause much
Speaker 1: scatter at all. Skin has a certain characteristic scattering effect,
Speaker 1: as do different metals and certain kinds of explosives. The
Speaker 1: machine paints an image of the back scattered results point
Speaker 1: by point, and an agent looking at that image can
Speaker 1: see things like metals, ceramics, and explosives attached to a
Speaker 1: passenger's body. The image that comes back is basically an
Speaker 1: image of a naked human body. It's a strip search
Speaker 1: without the stripping. It's fast and efficient. So what's the problem.
Speaker 1: There are three? Actually, First, many people don't like the
Speaker 1: idea of having photos of their nake bodies taken by
Speaker 1: any means. In addition, there are a number of stories
Speaker 1: of abuse e g. You get attractive women being more
Speaker 1: likely to be scanned or leaked images. Supposedly impossible, but
Speaker 1: obviously not since leaked images are on the Internet, and
Speaker 1: it doesn't help to have the kind of stuff happening. Second,
Speaker 1: because X rays involve ionizing radiation, many, perhaps most people
Speaker 1: have health concerns. All you have to do is look
Speaker 1: at the public reaction around any new nuclear power plant
Speaker 1: or the public acceptance of sunscreens to understand these concerns,
Speaker 1: even if the experts and the t s A say
Speaker 1: the machines are safe. The third problem is the perception
Speaker 1: that it's much ado about nothing, that the t s
Speaker 1: A represents security theater rather than actual security. This idea
Speaker 1: first took root because the t s A has not
Speaker 1: traditionally been very proactive. A terrorist had to bring explosives
Speaker 1: in the soles of his shoes before the t s
Speaker 1: A scan shoes. A terrorist had to bring innocent looking
Speaker 1: liquids to mix a bomb in the air before liquids
Speaker 1: were prohibited. Printer cartridges were not banned until explosives showed
Speaker 1: up in printer cartridges, and millions of people get onto
Speaker 1: subways every day without any screening at all, and that
Speaker 1: seems to work all right. In the case of the
Speaker 1: back scatter scanners, the t s A actually is being proactive.
Speaker 1: It is plugging a security hole before anyone exploits it.
Speaker 1: But in doing that, the t s A has met
Speaker 1: with significant resistance. And there's another problem that no one's
Speaker 1: really discussing right now. A passenger who is striped search
Speaker 1: still has a currently undetectable way to bring in explosives.
Speaker 1: The passenger could swallow plastic explosives wrapped in rubber or
Speaker 1: plastic along with a detonator. The human stomach can hold
Speaker 1: a couple liters of food and is fairly resilient. One
Speaker 1: person was known to swallow seventy eight forks and spoons
Speaker 1: before having to see the doctor. There's no easy way
Speaker 1: right now to detect this approach short of medical X
Speaker 1: rays or ultrasound. That leaves us with our current spectrum
Speaker 1: of choices. At one end of the spectrum, we could
Speaker 1: let passengers walk onto airplanes like we let them walk
Speaker 1: onto subway trains, zero security of any kind. At the
Speaker 1: other end of the spectrum, we could give naked passengers
Speaker 1: full body cat scans before every flight. Somewhere in the
Speaker 1: middle is a level of security that the majority of
Speaker 1: passengers will willingly accept. Apparently, full body X rays scanners
Speaker 1: maybe a little beyond that limit at this moment in history.
Speaker 1: For moral this and thousands of other topics. Does that.
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