I have often heard that lightning is attracted by any metal on your body such as golf clubs, metal coins and jewelry. This sounds like an urban legend to me becuase I can’t see why a lightning bolt that is trying to find the path of least resistance to the earth would deviate by maybe several metres and hit you just because you have a few coins in your pocket. Does anybody know what the truth is?
Thanks
A lightning bolt isn’t a thing, it’s a process. It’s like a ball rolling down a hill. If the ball hits a gully it will roll sideways for a while. That doesn’t mean it’s not being affected by gravity, it’s just that it’s always seeking the lowest ground and the gully happens to be it.
Same with lightning. A bolt of lighting is just electrons moving along charged pathways, always seeking the path. A piece of metal attracts them like a gully attracts a falling ball. There’s nothing out of the way to the electrons. The metal is simply the next logical bit of pathway.
I seriously doubt that having a few coins in your pocket would make a difference, but be careful swinging a golf club. The charge separation in the clouds (positive at top, negative at the bottom) causes objects on the ground to “feel” a voltage difference. This causes them to send out a weakly-charged, barely-illuminated “positive leader.” This leader can connect with the negatively-charged step leader reaching down from the cloud, completing the circuit and allowing the cloud to dissipate its charge to the Earth along that path (in this picture , lightning strikes a tree – you can also see two failed streamers, one coming off the tree and the other coming off of a power pole off to the left; in this picture you can see a failed positive streamer coming off of a building to the right).
In general, whether one of these streamers successfully connects is chance, but among the factors that increase the probability of success are: (1) height (the closer to the cloud the better); and (2) conductivity. So holding a golf club up in the air increases your chances of being hit, but your spare change does nothing. That said, if you’re standing up your body can send off a positive streamer as well (you can tell, 'cuz your hair will stand on end…).
By the way, if the lightning only misses you by a few meters you’re pretty screwed too, as you are a much better conductor than the air or the ground. That’s why you want to crouch down into a ball, so that the voltage difference from one end of your body to the other is minimized.
The more we learn about lightning, the more mysterious it is. We used to think:
Lightning always goes from sky to ground, never from cloud to cloud. Now we know intra-cloud lightning is common.
The sky iis negative, and the ground is positive. The “truth” changed several times, and now we know the polarity changes within a single storm.
Lightning will follow the shortest path to ground, striking the highest conductor. Usually, it’s true, but lightning doesn’t always follow the rules. Who’s gonna argue with lightning?
Lightning always goes down. No. A big storm often has strikes going in both directions. In a very tall storm, a big down strike is preceded by a “sprite” striking upward from the top of the storm
Getting back to your OP, lightning will strike a tree or pole coated with rainwater. Within many yards of a main strike, little branches can fan out from the bolt. Sparks can also come up from the ground.
In one storm, I was walking about ten yards behind another student at the U. of Evansville. He had an umbrella, and I didn’t. I did have coins, a wristwatch, and a belt buckle. Lightning struck the campus radio tower 100 yards away. We both went into the same dorm, and I heard him telling his friends he’d been struck, and sparks had flown out of his umbrella. I saw no bolt come down to him, so he must been sparked from below.
There is more, of course, but I’m an amateur, gleaning stuff from National Geographic and Nova.
I thought lightning was generally ground to cloud?
How can lightning be positively charged? Isn’t it made of electrons?
Lightning is the conduction of electricity from two areas of differential voltage via a breakdown of the nominally neutral intervening atmosphere into a charged plasma. As AskNott notes, the phenomena that collectively make up lightning are beyond the simple popular conception of lightning “traveling” from clouds to ground, but in general, the conductive medium doesn’t really go anywhere; it just provides a conduit by which the electric potential can be transferred, just as the wires in an electric circuit. And like copper wires, metallic elements or alloys in general are more conductive than non-metals or atmospheric gases, thus they are the preferred route (“path of least resistance”) to ground. That being said, the presence of a few nickels in your pocket isn’t going to increase your chance of being struck by lightning, since they don’t conduct to anywhere. However, walking around with a golf club or rifle over your shoulder may make you slightly more susceptible to being struck, and waving around on the clocktower during a thunderstorm is definitely contraindicated for anyone who isn’t trying to get their time machine going again.
Martin Uman’s Lightning is the classical text on lightning theory; although it has no doubt been superceded since its original publication, the treatment of the phenomena is comprehensive for its day and clear enough for nonphysicists to understand.
Stranger
There is far too much to cover, but the short answer is no. Lightning is no more made out of electrons than sound is made out of air. Of course without air, there would be no sound, and without electrons, there would be no lightning.
In a lightning strike, electrons are moving to be sure…and fast. But not far: Within a millimeter or so, an electron will run into an air molecule. if it hits hard enough (depends on the strength of the electric field, and the gas density) more electrons will be knocked loose from the air molecules. Stripped of these electrons, the air molecule becomes a positive ion, which can and does carry positive charge in a direction opposite the electron flow. The freed electrons run into other air molecules, ionizing yet more air. You end up with a “soup” made of positive ions, and disassociated electrons. This is plasma. If a lightning bolt can be said to be made of anything, it is this plasma, which contains charge carriers of both polarities.
Electrons are far more mobile than the ions, so they do carry most of the current, but not all.
Of course with both polarities present in the plasma, they are attracted to each other, and the positive ions won’t last long before they gobble up an electron. When this happens, a photon is emitted, and this is the source of the light from lightning, and neon signs for that matter.
Even with no discharge present, there are a few ions about. So when you charge something to high voltage, (either polarity) these ions will be drawn to, or repelled by the electrode. If the voltage is high enough, this will cause a chain reaction of ionization. This is known as a brush discharge, or St. Elmo’s Fire. Note that either polarity can cause this discharge. It is this sort of discharge that** jlrepka
** was referring to.
Unless it’s a 2-iron, because even God can’t hit a 2-iron.
Lightning thought it was attracted to metal, but as it turns out, lightning is just going through a “phase” right now and doesn’t fully understand its own wants and needs. Lightning has a history of abusive relationships (storms, thunder, etc.) and was stuck in the rut of thinking “I don’t deserve any better”.
At first, lightning was questioning its sexuality, thinking it might be gay, but as it turns out, it just hasn’t met the right conductor yet. My advice would be to just give it its space and let nature take its course.
Zerc, your insight about the importance of a small length of metal in your posession sounds right to me. And I’m a physicist and did a project involving lightning, once, with Martin Uman himself.
Many of the other posts raise interisting and useful points, but your original question, most importantly, seems like a direct strike.
As I had hoped, some people in this thread are really well versed on lightning. I’ll just fill in with tiny details about how the information was gathered, or at least what I saw on TV. Instrument-laden balloons are launched into storms to measure atmospheric charges at various altitudes. A single cloud tower may have layers with opposite charges. Rockets, trailing fine wire, can be launched into the cloud, in order to trip a strike into a given spot. Later, the trail of melted minerals from the surface on down can be dug up intact.
The things I don’t know about lightning could fill volumes. In fact, they do.
http://www.dailycognition.com/index.php/2007/04/27/story-of-a-man-who-was-struck-by-lightning-7-times.html
This lucky guy got hit by lightning a mere 7 times.
Fulgurites. Rare, both since the strike must hit an acceptable rock medium and because they’re obviously not overly apparent from the surface, but very cool indeed.
Fulgurites aren’t so very rare – they form all the time when lightning strikes sandy beaches. I have several examples in my house. They may be rare in the sense that they form a very tiny fraction of observed formations, but fossils are “rare” in that sense, too. They’re not so rare that they cost a huge amount of money to own. You can buy pieces of fulgurite for a couple of bucks.