unallowed movement through metal detector?
May 25, 2015, 6:54 pm
#1
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unallowed movement through metal detector?
Went through PreCheck at DCA recently. As I walked through the metal detector, I was stuffing my BP and DL into my shirt pocket. The TSA agent stopped me. "Sir, I can't have moving your hand into your pocket as you walk through." And she had me go back and walk through again.
Does this make any sense? Is there really a TSA policy on that, and if so, why? Granted, it's been 40 years since I graduated with a physics minor, but I am baffled. Horizontal motion is OK, but vertical is not, apparently? If my hand holds a coil, I'm creating the perfect eddy current to mask whatever I'm hiding in my shirt pocket?
Does this make any sense? Is there really a TSA policy on that, and if so, why? Granted, it's been 40 years since I graduated with a physics minor, but I am baffled. Horizontal motion is OK, but vertical is not, apparently? If my hand holds a coil, I'm creating the perfect eddy current to mask whatever I'm hiding in my shirt pocket?
May 25, 2015, 8:34 pm
#2
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I sure don't see any reason movement would be a problem. Yes, you'll change the currents created but I can't see how movement could lower the peak signal. It would either be neutral or cause both a decrease and increase--and how could the machine not be looking for the peak?
May 25, 2015, 9:34 pm
#3
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Went through PreCheck at DCA recently. As I walked through the metal detector, I was stuffing my BP and DL into my shirt pocket. The TSA agent stopped me. "Sir, I can't have moving your hand into your pocket as you walk through." And she had me go back and walk through again.
Does this make any sense? Is there really a TSA policy on that, and if so, why? Granted, it's been 40 years since I graduated with a physics minor, but I am baffled. Horizontal motion is OK, but vertical is not, apparently? If my hand holds a coil, I'm creating the perfect eddy current to mask whatever I'm hiding in my shirt pocket?
Does this make any sense? Is there really a TSA policy on that, and if so, why? Granted, it's been 40 years since I graduated with a physics minor, but I am baffled. Horizontal motion is OK, but vertical is not, apparently? If my hand holds a coil, I'm creating the perfect eddy current to mask whatever I'm hiding in my shirt pocket?
You're making the assumption that the person responsible for this "rule" - either someone at TSA HQ or, more likely, the TSA clerk at this checkpoint - understands the physics involved in a metal detector. Or knows that there is physics involved in the operation of the metal detector. Or can, at a minimum, spell "physics."
I wouldn't count on it.
May 26, 2015, 8:22 am
#4
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I sure don't see any reason movement would be a problem. Yes, you'll change the currents created but I can't see how movement could lower the peak signal. It would either be neutral or cause both a decrease and increase--and how could the machine not be looking for the peak?
And remember fisiks is phun.
May 26, 2015, 2:20 pm
#5
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Join Date: Jun 2005
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I have seen people asked to repeat the WTMD because they went through it to fast. When passing through (over) a metal detector a current is generated. But I believe what is also need is the time. i.e. total charge. Otherwise one might get too many false positives if just looking for a change in the current.
And remember fisiks is phun.
And remember fisiks is phun.