Re: Jurassic Park

[bdow@ee.ubc.ca (Bruce Dow)]

In article <mark-060793093244@128.157.9.145> mark@pokey.jsc.nasa.gov (Mark Manning) writes:
>> So there already *was* a short circuit, even without Tim touching
>> any of the wires. Actually, come to think of it, the fence looks
>> more as if it were made for climbing than carrying high voltage!
>> 
>
>Yeah, I remember you saying that.  Hmmmmm....hadn't thought about the
>cross wires.
>
>Ok, let me ask this - if you had a high voltage fence and you took a
>stick and threw it at the fence - would it zap the stick?  Also, if
>the stick were wet would it do this?
>

Another good question I thought about when watching the movie!
It's kind of a moot point in regards to the fence in the movie
since that was obviously not an electric fence design. 

I have seen real electric fences for cattle near here. They consist
of wooden posts with wires running along them (no cross wires,
though!). One of the wires running along carries the high
voltage. The voltage is applied in short pulses to save cost
and enhance the effect!

I remember the stick in the movie looked quite dry (although I
guess that was a high-humidity environment). On the cattle
fence the stick would have to be moist and touch the high-voltage
wire *and* ground simultaneously in order to get zapped. But with
the short pulse-length they use, the zap would not be visible.
The fence is design to warn the cattle away, not fry them!
I touched one of the fences myself and you get quite a shock,
but not any lasting pain or damage. I don't know what the
voltage is, but I doubt it's 10 kV!

I guess you have to be like a kid and suspend disbelief
in order to really enjoy some movies.

Lawrence asked why we were discussing this topic...

Well, in my case it's because our site doesn't 
get rec.pets.dinosaurs!!!

Bruce





-- 

Bruce Paul Dow,  undergraduate student, (third year)
Electrical Engineering (Computer Engineering Option)
The University of British Columbia (Vancouver, B.C.)
Member of Team 10, Developers of:  __Mail_System_X__