NYT story: Possible risks when electronics aren't turned off during flights

[tubemonkey]

Originally Posted by SeaBookGuy

Taking a break from your harp lessons to come back and enlighten us, eh?

Alt universe, don't ya know

[MikeFromHC]

Originally Posted by WillAdams

Given the danger a small, dense object represents in an accident, that alone is sufficient reason to require that people put the things away.

For those who feel that hardcover books represent a similar danger, try the following experiment:

- take an open hardcover book, throw it as hard as you can at a wall 6' away, observe the size of the dent (if any) which it makes
- repeat that w/ some small electronic device, compare the relative size of the damage

http://abcnews.go.com/GMA/story?id=128062&page=1

William

Pretty meaningless. KE= 1/2 MV^2 and that does not change.

The heavier object will hit with more force if they have the same velocity when they hit. It is the pressure exerted that will determine damage and in general a book will exert less pressure, but if an edge hits the wall it is likely to do more damage.
It's why we can push a thumbtack into a wall with less force than we can push our finger through the wall.
Note also that V is important.
Drop a 10 pound object from 1 foot onto your toe, then do the same with a 1 pound object from 10 feet...

[kacir]

Originally Posted by Sydney's Mom

If the question is electromagnet waves, then why does my kindle matter.

The vast majority of electronics doesn't matter. But they do not want to give flight attendants 6 months long training to recognise exactly which piece of electronics could be dangerous.

Also, passenger next to you who is operating his WiFi enabled mobile phone through bluetooth handsfree and using GPS unit, while talking to his son in row 5 on non-FCC-standards-compliant toy Walkie Talkie, illegally imported from China, will start to quarrel with hapless flight assistant that why should HE switch off his devices when you are allowed to operate yours.

Last but not least, NOBODY is willing to make (and be responsible for) the list of devices that are OK to use

[Sydney's Mom]

Originally Posted by kacir

Also, passenger next to you who is operating his WiFi enabled mobile phone through bluetooth handsfree and using GPS unit, while talking to his son in row 5 on non-FCC-standards-compliant toy Walkie Talkie, illegally imported from China, will start to quarrel with hapless flight assistant that why should HE switch off his devices when you are allowed to operate yours.

[WillAdams]

MikefromHC --- you forgot to include air resistance and surface area. An opened book will _not_ be able to travel so fast as to cause significant damage unless it happens to orient itself so that it closes --- even closed, it's not likely to be able to travel so fast as to do the kind of damage which a hard metallic object will.

[Bricorn]

Originally Posted by DMB

Until a few years ago phones were forbidden in hospitals because there was a fear they would interfere with various medical machines. That danger seems to have receded now.

To be fair, we had analogue phones then. Modern digital phones radiate less energy.

[CWatkinsNash]

Originally Posted by Sydney's Mom

If the question is electromagnet waves, then why does my kindle matter. Of course, I don't have the wireless on, but the flight attendant says "anything with a battery" So, I place it in its case, on my lap, and read secretly. As I suspected, that is a rule just so the flight attendants don't have to make decisions - is it a phone, a music player, a game boy . . .

Only narrowband electromagnetic interference is from wireless transmitting devices. Broadband EMI can be emitted from many electronic devices. Hence, the "anything with a battery", including your Kindle. Not only does a blanket rule prevent having to itemize "allowed items", it also covers the possibility of a malfunctioning device emitting more than the usual amount of EMI. (It's been a while since I studied this stuff, but I think I've got that right.)

[Sydney's Mom]

Yes, but I don't turn it off, I just put it to sleep (most of the time, I just don't turn the page). Does it still emit EMI?

[MikeFromHC]

Originally Posted by WillAdams

MikefromHC --- you forgot to include air resistance and surface area. An opened book will _not_ be able to travel so fast as to cause significant damage unless it happens to orient itself so that it closes --- even closed, it's not likely to be able to travel so fast as to do the kind of damage which a hard metallic object will.

I assumed that "same velocity when they hit would cover it.

However it is easy to throw a book that keeps it's covers closed. Send me ten cell phones and I'll throw them and a book against a wall to test the idea.

(Don't complain, I could have said ten hearing aids )

In an airplane it probably does not matter as a book or a hering aid traveling at 100 plus MPH is going to do damage - if it hits you before you hit the front of the plane or vice versa.

[CWatkinsNash]

Originally Posted by Sydney's Mom

Yes, but I don't turn it off, I just put it to sleep (most of the time, I just don't turn the page). Does it still emit EMI?

It shouldn't emit much at all. A lot of things utilize a 'sleep state' rather than turning off these days, including my iPod Classic and Kindle. It's a very low power state so unless it was malfunctioning terribly I imagine it would barely be detectable.