On page 211 of SR4A, it says,


Water is made of free moving molecules, but it is a liquid, not a gas. Is the barrier created by Physical Barrier permeable by water, or for that matter other liquids?

hehehe....

The more I try and answer this, the more I can't. A solid is simply a freakin' huge molecule, after all...

The spell description specifically says air and gasses, so for water I would say no; you could argue that the hydrostatic interactions between the water molecules prevent it getting through if you are looking for a technical reason.

Saying that, it could be argued that water as a small molecule (at 18 its molecular weight is less than larger more complex molecules such as smoke, after all) might seep through the barrier slowly, especially if the pressure is high. We would definitely be talking seeping here, so the barrier should to all intensive purposes be effective against a water hose or water jet spell. Not sure I would like to be the mage testing it out as a makeshift escape bubble from a sinking submarine or ship, though ...

GM call, either way.

But a magician is not a chemist or physicist, so he might not know that. He who created the spell believes a molecule is something very very tiny, less than nanometer size. You see, it's about believe, which makes this spell well suiting to a shaman, but a hermetic might struggle with the formula.

If a molecule is going to slip through unimpaired, a monowhip should slice through one just fine...

They probably wanted to say "it's air permeable but otherwise solid" but failed chemistry forever.

Guys, guys, they said 'anything the *size* of a molecule' can pass… they just didn't say *which* molecule. Clearly it's a smallish one.

I would say yes, liquids can permeate through a barrier, but very slowly.

So, if you use Barrier as a rain-shield, for example, drops of water would collect along the inner surface and drop down, but the bulk of the downpour would be deflected.

A monowhip would be stopped, because of its length, not its thickness.

Bye
Thanee

And solids are not molecules in any instance. There are some freaking big molecueles out there... True.
For example a leaf is not a molecule, a steelbar is not really a molecule, plastic is not a molecule and so on.

But yes, some liquides would be able to pass.

If you see someone hiding behind a Physical Barrier, why not just steam them out? It doesn't block gasses, so just throw some superheated water at them. Does it block the Smoke Indirect Combat Spells?

Why would you have some superheated water handy?

Sounds like a GM call. By default (just because they're spells), you'd assume it blocks all indirect combat spells, even Light, Sound, etc.

In case there are Physical Barrier spells? Maybe you're playing a Seattle game where it's wet a lot, and you Fireball the area, causing little damage to the people in the barrier but superheating the water around it?

Then why not just shoot a fireball at the barrier? The superheated air goes through and everybody is toasted...

Haha! It's not *that* wet, and I'm not even sure SR4 has any rules for affecting water (or air) in that way.

Proteins are molecules. The largest known protein has an empirical formula of C₁₆₉₇₂₃H₂₇₀₄₆₄N₄₅₆₈₈O₅₂₂₄₃S₉₁₂.

Molecules are made of atoms with covalent bonds (they share electrons). Solids are made of atoms or molecules with any kind of chemical bonds that prevent them from flowing. There are solids only made of covalent bonds, like diamond and silicon, which can be considered as a single molecule.

That's why the rule refers to some specific (unnamed) reference molecule.

I have always interpreted it as being like so...

If the object in question is a molecule or smaller, then it passes through. Thus a bullet would not pass through the barrier. Air will pass through. Smoke will not. Water will be stopped but will seep through.

If the compound in question can be dissipated to where it is naked to the human eye, it can pass through the barrier. So aerosol knockout agents and the like, you are going down. Someone floods the area with CO2, you are going to have a bad day.

Area flooded with water? You get to watch a slow & lingering bad day.

A bullet made of diamond.

For when you want to kill someone *so badly* that you don't mind spending $10,000 per bullet to do so.

~R~

@Neraph
Well, even a diamond does not really work... The problem would be dirt. One other molecule attached to the surface would be enough to stop break the rule...

@Raiki
Nope. To have at least a chance you would need industrial grade diamonds. Natural diamonds would not work at all. They are not "pure"...

Since its *magic* i'd say it allows 'air' (and 'gas' would be equivalent to air) so that people can breathe but stops everything else - I think it is bad to go to far with physics in regards to magic.

The question that remains then is the following.

How deep underwater can I go before the water pressure actually harms my barrier 'bubble' i've made.

Since air gets through the barrier, either the bubble would float, or all the air would rise to the surface of the water making the barrier collapse upon itself until you are the only thing in it.

Well, since the bubble does not defy gravity (levitate spell does that) then as long as the people inside the bubble weight more than the air it should sink.

Ooh, I like the shrinking bubble theory. The deeper you go the smaller the bubble becomes as it collapses unto itself, crushing the person inside it as it becomes smaller and smaller due to crushing pressure.

*squish*

The gas would escape, leaving a vacuum.

@Neraph

No, not really.

Schrodinger's mage?

And considering that a pure diamond crystal is incredibly easy to make with any nanotech and some carbon feedstock, you could easily get a monomolecular crystal.

Interesting - so why dont we have "Synthetic Diamond Bonelacing" - Might even be cheaper than Titanium, would give it more Ballistic but less Impact (Harder but might be more brittle?)

Diamond may be made from carbon atoms, but they are covalently bonded in a solid matrix to make a pretty freaking large molecule, so a diamond bullet would definitely not pierce a Physical Barrier.

As for the air bubble in water, it would be GM call as to whether its contents (folks plus air) would be less dense or more dense than water, and thereby whether it floated or how far it sank until it equilibrated with the increasing density of the pressurised water; also as previously stated whether the water would seep in or not.

Good question as to whether spells such as Smoke, Steam, Fireball or Lightning Bolt would get through. Seeing as they are effectively gaseous forms (as opposed to liquid or solid) I would say yes.

The whole Dikote™ industry disappeared suddenly...

Maybe all bones are already considered to be dikoted?

Diamonds are hard, thats not nessesary a good thing...
Diamonds splinter...
And I am not certain if the destruction of their matrix absorbs a lot of energy. As far as I know, ceramics are better in this case..

I guess the razorboy/girl/industry industry had a copyright claim - Especially the Gilette Gang

When confronted with such questions, I have two rules:

1. Magic works... like magic. It's better to go with how the spell would work in a fantasy story/people's imagination than to think about how it physically works.
2. There are probably many variations of the same spell.

In that particular case, I'd say that water doesn't get through because if I imagine casting such a spell under the rain or under a waterfall, I don't imagine water going through.

I'd say just interpret it in a way that make sense.

It seems the folks who wrote up spell descriptions don't understand physics or chemistry.

I remember asking once about Improved Invisibility. With the whole bending the electromagnetic spectrum around you so that you can't be detected.

Never mind that if the light can't get to your retinas that you're effectively blind too.

Magic just doesn't make sense is all.

It doesn't have to make sense it's Magic!

How it works, explained in detail.

This is my biggest gripe with the invisibility spell - it is an illusion spell that bends light, regardless if it works on humans or machines and should have been a manipulation spell instead.

Instead they should have made the following:

Illision Invisibility
A blind spot spell that simply tells everything you are not there and visual identification is impossible unless the target defeats the spell, no visual aid gets any bonuses. Not even Ultrasound works because the target doesnt even register the information because his brain is being fooled to not seeing anything. It would also work on drones and people alike but higher drain than the manipulation version.

Manipulation invisibility
Physically bends light and fools everyone but anyone observing the target gains spotting bonuses from other senses - A weaker version but that works on drones and people alike.

The same goes for silence spells - The illusion version would fool the brain/sensor to not register the sound even if it is heard while a physical manipulation spell would actually cancel out the sound by blocking the airwaves.