Lois & Clark Forums Forums General Discussion Lois & Clark Why lead?

Does anyone have any ideas (other than it being a convenient plot device that is well established in the Superman universes, of course) why Clark can't see through lead? What is it about lead, as opposed to, say, tin (which is just above it in the periodic table), which makes it visually impenetrable for him? And why only lead and not other elements as well?

I know, I know...I am asking a lot -- I am asking for things actually to make sense in the LnC universe. This is probably yet another example of something I should not look at too closely but just swallow whole in my suspension of disbelief. Still, I was curious whether anyone might be able to come up with a plausible explanation.

Joy,
Lynn

I think the original choice of lead as a substance that he can't see through has to do with his "X-ray" vision. Lead is the most common substance used as shielding for X-rays.

I think we've all agreed that his vision gizmo isn't actually the same type of X-rays. But I think the lead thing has just continued as part of cannon.

There certainly are other things that he shouldn't be able to see through based on that theory...plenty of other things that CAN be used as shielding from radiation/X-rays.
In general, the thickness of a material to attenuate (shield) x-ray radiation is dependent upon the energy of the x rays, the material's chemical composition, and the material's density. Which explains why tin (specifically) doesn't work - the density is much different from lead...but something like tungsten (which is actually better at shielding from radiation - just a lot more expensive) should also block his vision. Actually, ironically, steel is also attenuating for radiation - not as well as lead, would just require more material...but under that theory, Clark shouldn't be able to see through really thick stteel either.

I think the original lead theory was based off actual X-rays and then just kept as a single substance for simplicity.

Interesting thing to think about and nitpick. <g>
Jill

Hi Jill,

Thanks for that detailed explanation. It makes sense as far as it goes. Now have you an explanation for why the very thin layer of lead present in a coat or two of lead paint would be sufficient to block his vision?

Joy,
Lynn

@Lynn: I don't mind Clark looking through my clothes. :p

Hi Lynn. Even the thin layer of lead in lead based paint will block his vision because it is very dense. Doc Jill's explanation was right on. Even a thin coat of lead works. It has to do with the wavelength of the X-rays. Maybe he might see some blurry stuff, but his brain couldn't figure out what it was.

Artemis

Hi Artemis,

Really? I was thinking that it would need to be thicker than that; kind of like colored cellophane -- People can see through a single sheet of it, but they won't be able to look through a group of such sheets bundled together. I would have thought that the lead in the lead pain would be so attenuated that it might make the wall its on translucent rather than transparent to Clark, but I wouldn't have thought it should turn it opaque.


Joy,
Lynn

This is not astronomy, so I don't know the answer, but I'm guessing!

I agree with you, Lynn, that a thin layer of lead wouldn't necessarily be sufficient to block his vision. I do know that there are certain kinds of super-energetic radiation out there in space that you can't block unless you you can hide behind miles and miles of lead, and I'm not sure that even that much lead would be sufficient.

Personally, I can't help thinking that lead is a "black magic element", as it were. It is well known that Eros, son of Aphrodite, will shoot golden arrows into people's hearts, and when he does so they will fall in love. Less well known is the part of the myth that says that Eros also has arrows made of lead, and if he shoots such an arrow into a person, the individual will feel hatred and revulsion.

So I think that... let's put it like this... the word "lead" sounds ominous, more so than the word "steel". Anyway, since Clark himself is "the Man of Steel", why should steel cause him trouble? It somehow doesn't "feel right" from a "magical" or "mythological" point of view that "one's own lucky substance" would be troublesome for "a mythological being". Let's not forget that Clark, or at least Superman, is a myth!

As for tungsten, excuse me, but who has ever heard of it? Yes, some people have, obviously, but if you compare the number of people who know the word "lead" and recognize it as something vaguely "evil", and compare that with the number of people who know what tungsten is... well, there is no comparison.

Ann

It has to do with the wavelength of the X-rays vs. the size of the lead molecule and the density of it. The wavelength of X-rays is around 1 nm (nanometer). We see at ~400 nm (purple) to ~700 nm (red). For scale a nanometer is, according to wikipedia:


Lead paint is lead chromate (PbCrO4). A single brushstroke will be several molecules thick. Thus it is as effective at blocking X-rays as a sheet of lead foil. Lead foil has been used in several stories to protect Clark from the effects of Kryptonite. Lead is very malleable and easy to manipulate, which is why it was used extensively for centuries until the damage to human beings could be observed.

The other major difference between Clark "seeing" with X-ray vision and X-rays as diagnostic devices is that the latter is an active system. X-ray machines emit X-rays, bombard the subject and you get a shadow picture.

Clark's vision is not active. He "sees" at one nanometer like we see at 600 nanometers.

So that's an explanation of why lead paint works just as well as lead shielding.
Artemis

Thank you, Ann and Artemis, for your explanatory posts. It's nice to see that Clark's X-ray vision being blocked by lead isn't quite as far-fetched (in the LnC universe, of course; not in our own!) as it had appeared to me.

Joy,
Lynn

I thought it was just because of lead's molecular density or something. Then again, I'm just a language teacher. I shouldn't talk. Oops! Too late. lol.

I found this little Wikipedia article about lead shielding . I guess I still don't understand why lead works better than most elements when it comes to shielding, while at the same time it doesn't work as well as tungsten, which has a lower atomic number.

But lead is a common element that has been widely used for centuries if not millennia, and it does work better than most elements at blocking radiation. Oh well.

Ann

The world isn't logical, it just is.
Artemis

And that goes tenfold for the LnC world.


Joy,
Lynn

Well, I guess it has something to do with the configuration of electrons around the nucleus. I do know that metals are metals because of the configuration of electrons around their nuclei. It's because they have a few "extra", not so strongly bound, electrons in their outermost "electron shell" (if that is what you call it in English, too). Oxygen, on the other hand, reacts so strongly with almost everything else also because it has a "shortage" of electrons in its outermost "electron shell".

Lead is a metal but not a "typical metal", rather a "transition metal". More important may be the fact that lead is a "heavy metal" with a large nucleus, and its atomic number is 82, meaning that it has a total of 82 protons and 82 electrons (I think). Tungsten, which is even more efficient at shielding against radiation, has an atomic number of 74, which means that it, too, is a heavy metal, and it has 74 protons and 74 electron, eight fewer than lead. I think the number eight rings a bell, because I know that there are only so many electrons that you can fit into an electron shell, and I think eight might be an important "transition number". (Wouldn't you know that oxygen has atomic number eight?)

But if you are looking for the element with atomic number 66 (74 minus 8), you come to a strange element named dysprosium. Have you heard of it? Didn't think so. The element whose atomic number is 90 (82 plus 8) is thorium. Well, I've heard more about thorium than I've heard about dysprosium, so maybe it's used for something, but it is sure more unusual and more expensive than lead.

Periodic table

Ann

It's a rare earth, which are really odd elements.
The name dysprosium is the equivalent in English of "unobtanium" which is used frequently in American movies as a McGuffin (i.e. a plot device that moves the action along without being too specific on what it is that everyone is after.)

From our friend wikipedia:
It is used in nuclear fuel rods and has many desirable properties as a shield. Hence, in it's way, it's doing the same job as lead, just for a different wavelength.

If you really study the Periodic Table, it really holds a wealth of detail and information and is an amazing construct in terms of understanding the real world.

Artemis