h a l f b a k e r yMake mine a double.
add, search, annotate, link, view, overview, recent, by name, random
news, help, about, links, report a problem
browse anonymously,
or get an account
and write.
register,
|
|
|
Please log in.
Before you can vote, you need to register.
Please log in or create an account.
|
I recently learned that the tentacles on jellyfish have thousands of spikes that when stimulated by an electric field shoot out of the tentacle at over 20000 times the acceleration due to gravity. It is that force that introduces the venom into a persons blood stream. Now if the spikes were already out
they would not be able to penetrate skin.
So I propose selling a device that generates a strong electric field around swimmers and divers, thus protecting them from jelly fish. The field would be jellyfish specific.
This idea has already be used for sharks, because sharks apparently cant stand electric fields.
Box jellyfish info pages
http://www.jcu.edu.au/interest/stingers/
In Australia, most things are deadly! [ConsulFlaminicus, Oct 09 2005]
Large pdf file giving details of Nematocycts
http://www.ucihs.uc...eele/Kass-Simon.pdf
Max 40,000g acceleration. Initial response time in the 10s of microseconds. Full response time about 3ms. Electrical stimulus not mentioned, apart from mechanical to electrical in the cyst itself. [Ling, Oct 10 2005]
If they do get you...
Piss Plasters
[theleopard, Feb 04 2008]
[link]
|
| |
I am not sure how you would generate an electrical field in the open ocean, but this is an interesting hypothesis. Would electrocuting a jellyfish mean that it could not sting? Hmmm... |
|
| |
People have avoided jellyfish stings by wearing nylons. Not the most masculine of swimwear, but you wouldn't catch me in the ocean with jellyfish about anyway. |
|
| |
Electric stimulation is the trigger for the spikes. They extract jellyfish venom by shocking cut tentincles. |
|
| |
the speed of gravity?? wtf?
10m/s/s? |
|
| |
Or you can just pretend to be one of them with a jellyfish propulsion wetsuit... |
|
| |
[webby] - According to relativity, the speed of gravity should be the speed of light (although I don't think this has yet been measured). As the speed of light is 300,000,000 m/s, this would put the speed of jellyfish spikes at around 6,000,000,000,000 m/s. That's real fast. |
|
| |
That’s why they hurt wagster. Since they are violating relativity, God is spanking their tenancies with a ruler. |
|
| |
[webby] m/s/s is the unit of acceleration, not speed. 9.81 is the amount by which an object will accelerate under gravity. |
|
| |
p@Y Up OR tHe jElLyFiSh gEtS It. |
|
| |
Its the fastest biological mechanism known to man. |
|
| |
Faster than the cone response in the eye? |
|
| |
5 femtoseconds or so for the rhodopsin response to light--a few orders of magnitude faster response than the jellyfish nematocysts which is, by contrast, measured in the milliseconds. |
|
| |
Like I said, fastest biological mechanism known to man. |
|
| |
Would the electrical current be so 'large' that, although it pre-triggers all the Nematocysts, it also initiates fibrillation in the swimmer's heart? |
|
| |
My post grad work was on Stomatopods (which have the fastest macroscopic mechanical movement of any animal - when they trigger their 'clubs' or 'spears'). In the same lab was a world authority on nematocysts, who always insisted that the nematocysts of Chironex fleckeri, the 'Box Jellyfish' of the Indo-Pacific, represented the fastest (by some large margin) microscopic mechanical movement of any animal. And [bristolz] is of course correct when she points out that the rhodopsin response to light is the fastest (known) electrochemical 'movement' in animals. |
|
| |
Interestingly, both the Stomatopod stab/spear/club and the nematocyst cap opening and uncoiling rely on a sophisticated and highly potentiated 'latch' mechanism, though the Stomatopod strike is endogenously controlled and the nematocyst uncoiling cannot be controlled by the jellyfish - it happens purely in response to external mechanical stimulation. |
|
| |
Update on fastest mechanical movements: |
|
| |
Stomatopod (species measured was a Peacock Mantis Shrimp): peak speed 23 meters per second, peak acceleration 8,000G |
|
| |
Trap Jaw Ant: peak speed 17 meters per second, (can't find peak acceleration figure) |
|
| |
Nematocyst: peak speed 3-5 meters per second, peak acceleration 24,000G |
|
| |
23 meters per second is still only around 80kph. |
|
| |
This has set me thinking - if urine is such an effective anti-venom, maybe this is why mice are incontinent - they evolved in the sea, surrounded by their own personal (mouseonal?) cloud of anti-venom.
[cf] You forgot "Yorkshireman spotting loose fiver on pavement - speed c / 10, peak acceleration unmeasurable." |
|
| |
Hey, what if you could just sprinkle some salt on the jellyfish like you do, slugs? Doeh! Salts already in the ocean. Perhaps a chemical solution could cause the jellyfish's tenticle to remain in a constant state of erectness (hmmm Viagra!) Just pee out lots of Viagra and that should keep the jellyfish from hurting you! |
|
| |
Wow, [Consul] - you really have been surfing today haven't you. |
|
| |
So use a weak organic acid to deal with the jelly fish? I love basic chemistry. |
|
| |
The number in the idea is 20000 times the acceleration due to gravity. 20000 times 32 ft/sec = 640000 ft/sec. I have no clue how long a nematocyct is. |
|
| |
Nor, evidently do you have a good handle on basic kinematics. Not sure why you need to know how long the nematocyst is. |
|
| |
At 20, 000G's, acceleration is ~200,000m/(s^2) |
|
| |
So, if it is accelerating for 1/10,000 of a second, you get a resultant velocity of.. 20m/s. So we can presume that for ~20m/s the nemato-thingy is accelerating for ~1/10,000 of a second. (I know, ... "g" is 9.81, not 10, but it's easier this way) |
|
| |
If you start putting distance into kinematic equations, it gets a little more complicated. In SI units, these are the equations to use: |
|
| |
-from memory. cool. remember your sign conventions. |
|
| |
Where Vf = final velocity, Vi = initial velocity, A = Acceleration, D = distance, T = Time. |
|
| |
And of course, these only work for SI units. |
|
| |
Oh, by the way - we live in the tropics of Australia - and regularly see lost and lots of boxies. I was frolicing about near some the other day. We do a lot of boat trips where we land and camp from the boat, often in rather remote locations - invariably if it's summer you will see lots of boxies as you are hopping out of the boat. We always keep vinegar handy. But mostly, we just have a couple of packets of stockings handy. I still try and dodge the bastards, but have been hit a few times and am yet to be stung through the stockings. |
|
| |
As was mentioned above, not very masculine, but neither is screaming, crying uncontrollably, shitting and pissing yourself and eventually succumbing to cardiac arrest. |
|
| |
Christ, but they're evil little fuckers, aren't they? |
|
| |
//And of course, these only work for SI units//
Huh?
OK, it may be difficult converting to furlongs per fortnight, but the equations work just as well. |
|
| |
-I thought I posted this already- |
|
| |
The equations do work with non-SI units, so long as care is taken to obey convention - it helps to do a unit analysis to confirm with imperial calcs. Some operations with imperial units require exotic factors and constants - well, at least more so than with metric anyway. The equations really only describe the relationship between velocity, constant acceleration, distance and time <at non-relativistic speeds>. |
|
| |
Anyhoo - I hate stingers <jellyfish>, part of why I love turtles so much I s'pose. |
|
| |
Give the idea a whirl, if it works I want a free trip to australia. |
|
| |