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Vortling
2007-04-15, 03:20 PM
Does the grease created by the Grease spell burn? I've looked through the online srd, the player's handbook, and a brief search on the dnd main site and haven't found anything indicating one way or the other about its flammability. If there aren't any specifics on this, how would you rule on it if you were DMing? Thank you.

Belkarseviltwin
2007-04-15, 03:28 PM
Yes it does. Or at least I think so, as setting fire to it is an acknowledged tactic.

Necromas
2007-04-15, 03:31 PM
By RAW I don't think it says anywhere that the grease it creates is flammable, but I'd imagine you could set it on fire just as if you dumped a bunch of lamp oil on the ground and lit that.

TheOtherMC
2007-04-15, 03:32 PM
By the way that forest burned last week I'd think so....


Anyone want me to elaborate?! <_< >_>

Caledonian
2007-04-15, 03:33 PM
The spell doesn't say. However, it's summoned fat, so I suppose so.

However: raw grease doesn't burn easily. It would intensify the burning of an already-combusting material, but even a thick layer of grease over stone or soil would tend to put out things like torches instead of burning itself.

Vortling
2007-04-15, 03:48 PM
By the way that forest burned last week I'd think so....


Anyone want me to elaborate?! <_< >_>
Yes, sounds like you had fun with that. Caledonian: You raise some very useful points :smallsmile:

Ikkitosen
2007-04-15, 04:18 PM
Grease as per the first level spell does not burn - there's a second level version that is identical in every way (IIRC) except that it IS flammable. The spell has a stupid name too - Incendiary Slime, from Complete Mage.

Renegade Paladin
2007-04-15, 05:51 PM
No, it doesn't. You're looking for incendiary slime.

martyboy74
2007-04-15, 05:58 PM
However, placing Explosive Spell metamagic on it does create a minefield.

Caledonian
2007-04-15, 06:05 PM
Grease as per the first level spell does not burn -

The spell description doesn't say so. It's implied that the grease is related to pork fat or butter by the material components needed, and both of those things will burn - but not easily. A major fire is necessary to induce combustion, and the fire doesn't spread easily.

Ikkitosen
2007-04-15, 06:18 PM
The spell description doesn't say so. It's implied that the grease is related to pork fat or butter by the material components needed, and both of those things will burn - but not easily. A major fire is necessary to induce combustion, and the fire doesn't spread easily.

The existence of an almost identical spell a level higher that does burn implies that Grease burns in no meaningful manner.

If you'd like to rule that a major fire can burn Grease then fine. What difference will it make?

Caledonian
2007-04-15, 06:22 PM
If you'd like to rule that a major fire can burn Grease then fine. What difference will it make?

1) You can increase the size of an already-burning fire by casting Grease upon it. Instant accelerant.

2) You can't extinguish an existing fire by casting Grease upon it. If the grease were truly nonflammable, you could put out small fires very effectively by smothering them in such a fashion.

the_tick_rules
2007-04-15, 06:24 PM
test this theory out, in your house if possible.

Annarrkkii
2007-04-15, 09:10 PM
Does the spell say that the grease is flammable? No? Then it doesn't burn. In fact, the spell doesn't even say that the grease exists, per say, just that things are slimy from it. You can cast it in a burning house, sure. Then you have a slippery burning house. Woo hoo.

Phoenix Talion
2007-04-15, 09:19 PM
Does the spell say that the grease is flammable? No? Then it doesn't burn.

Does the spell say that the grease isn't flammable? No? Then it burns.

I'd say, houserule it. I'm inclined to say yes, it does burn, just because that's way more fun.

Ikkitosen
2007-04-16, 06:08 AM
1) You can increase the size of an already-burning fire by casting Grease upon it. Instant accelerant.

2) You can't extinguish an existing fire by casting Grease upon it. If the grease were truly nonflammable, you could put out small fires very effectively by smothering them in such a fashion.

1) Except that an accelerant needs to be more flammable than the fuel that is already burning, and we've agreed that Grease doesn't burn well, if at all.

2) I suppose if the fire were limited to a single solid surface (unlikely - surfaces on fire are rarely solid) or a single item you could smother them with a Grease spell. Inventive, but IMO would be relatively ineffective (compared to, say, dousing with water).

And seriously, does this level of nit-picking make you enjoy D&D more?

Rigeld2
2007-04-16, 06:14 AM
Does the spell say that the grease isn't flammable? No? Then it burns.
Does the Animal type say that Bears dont have lasers coming out of thier eye sockets, giving them an instant kill gaze attack? No? Then they do.

Tor the Fallen
2007-04-16, 06:19 AM
Does the Animal type say that Bears dont have lasers coming out of thier eye sockets, giving them an instant kill gaze attack? No? Then they do.

Really?
Wizards reall screwed up on their CR, then. Do those guys even playtest what they design?

Caledonian
2007-04-16, 06:25 AM
1) Except that an accelerant needs to be more flammable than the fuel that is already burning, and we've agreed that Grease doesn't burn well, if at all.

There's a reason grease fires can be a major problem in kitchens. Once grease begins to burn, it burns fiercely. An existing fire would be augmented by being Greased quite significantly.


2) I suppose if the fire were limited to a single solid surface (unlikely - surfaces on fire are rarely solid) or a single item you could smother them with a Grease spell. Inventive, but IMO would be relatively ineffective (compared to, say, dousing with water).

Actually, if the grease were nonflammable, it would be far more effective than water. Particularly since all of the burning object would be covered, which you can accomplish only poorly with water.


And seriously, does this level of nit-picking make you enjoy D&D more?

This isn't "nit-picking".

Rigeld2
2007-04-16, 06:27 AM
There's a reason grease fires can be a major problem in kitchens. Once grease begins to burn, it burns fiercely. An existing fire would be augmented by being Greased quite significantly.
Cite the rule that says Grease is highly flammable.

Caledonian
2007-04-16, 06:31 AM
Does the Animal type say that Bears dont have lasers coming out of thier eye sockets, giving them an instant kill gaze attack? No? Then they do.

Create Water doesn't say that it can be used to put out fires. Therefore, it can't. Does that seem right to you?

Grease doesn't just say that it makes surfaces slippery, it says that it conjures a thick layer of grease. Greases burn when they get hot enough, like fat in general. Suggesting that every possible use and consequence of a spell must be explicitly listed in the spell's description is just silly.

martyboy74
2007-04-16, 06:32 AM
Does the Animal type say that Bears dont have lasers coming out of thier eye sockets, giving them an instant kill gaze attack? No? Then they do.
I think that this is a side effect of the rule the "Everything burns unless specifically stated not too", laid down by the Players Union in '95.

Caledonian
2007-04-16, 06:46 AM
Will we next be treated to the argument that the objects created by Major Creation don't burn because the spell description doesn't explicitly say they do?

Grease, by the RAW and basic logic, cannot be a substitute for burning oil (which by RAW only does minor damage for a short time), as actual grease isn't that flammable. Logic dictates that the substance IS flammable under the right conditions, just like normal grease.

Tor the Fallen
2007-04-16, 06:48 AM
Anyone ever have to deal with a grease fire? Don't throw water on it- it will explode.

Rigeld2
2007-04-16, 07:02 AM
Grease doesn't just say that it makes surfaces slippery, it says that it conjures a thick layer of grease. Greases burn when they get hot enough, like fat in general. Suggesting that every possible use and consequence of a spell must be explicitly listed in the spell's description is just silly.
Everything will burn if it gets hot enough. Suggesting that they would leave out something as important as being flammable is silly - plus overpowered. Suggesting that you can light a puddle of grease aflame would make the spell into a first level fireball... that lasts one round per level.

Tor the Fallen
2007-04-16, 07:06 AM
Everything will burn if it gets hot enough. Suggesting that they would leave out something as important as being flammable is silly - plus overpowered. Suggesting that you can light a puddle of grease aflame would make the spell into a first level fireball... that lasts one round per level.

It'd probably only do 1d3 damage/round to creatures standing, lying, doing push ups, etc, in the 5ft square that was burning. Burning would probably also cause it to go away sooner rather than later.

Since grease requires relatively high temperatures to burn, what if you required it to take 6 fire damage in two consecutive rounds? This would require either a lucky roll with a flaming weapon, or spending two full rounds holding a torch to it.

Rigeld2
2007-04-16, 07:09 AM
It'd probably only do 1d3 damage/round to creatures standing, lying, doing push ups, etc, in the 5ft square that was burning. Burning would probably also cause it to go away sooner rather than later.
So, it does free damage for simply existing, because the point of the spell is to make creatures not move while inside it.


Since grease requires relatively high temperatures to burn, what if you required it to take 6 fire damage in two consecutive rounds? This would require either a lucky roll with a flaming weapon, or spending two full rounds holding a torch to it.
As a houserule it sounds fine. RAW it doesnt burn tho.

Tor the Fallen
2007-04-16, 07:14 AM
RAW it doesnt burn tho.

Well, by RAW it doesn't not burn, which mean it may burn, and as it's grease (nonmagical at that, as there's no SR), which DOES burn in the real world (just like wood, which, since it has a hardness of 5, can't be damaged by most mundane sources of fire, is also assumed to burn), grease DOES burn. The rules just don't specify the necessary conditions for it to ignite.

Caledonian
2007-04-16, 07:19 AM
Everything will burn if it gets hot enough.

No.


Suggesting that they would leave out something as important as being flammable is silly - plus overpowered. Suggesting that you can light a puddle of grease aflame would make the spell into a first level fireball... that lasts one round per level.

Um, no. I have explicitly said that the grease isn't flammable in that way - because actual grease isn't flammable in that way.

Oil is far more combustible than grease is. It's not a first-level fireball at all.

Caledonian
2007-04-16, 07:22 AM
RAW it doesnt burn tho.

Wrong. As Tor points out, unthinking adherence to the rules means that wood doesn't burn, since the RAW doesn't explicitly say that fire overcomes wood's hardness.

But wood is wood, and under the right conditions, it will burn.

Tor the Fallen
2007-04-16, 07:24 AM
Well, by RAW it doesn't not burn, which mean it may burn, and as it's grease (nonmagical at that, as there's no SR), which DOES burn in the real world (just like wood, which, since it has a hardness of 5, can't be damaged by most mundane sources of fire, is also assumed to burn), grease DOES burn. The rules just don't specify the necessary conditions for it to ignite.

You know, if you had to bear the weight of comma splices upon your visage, you'd look like Dorian Gray if he didn't have that nifty painting. Srsly.

Tor the Fallen
2007-04-16, 07:25 AM
Wrong. As Tor points out, unthinking adherence to the rules means that wood doesn't burn, since the RAW doesn't explicitly say that fire overcomes wood's hardness.

But wood is wood, and under the right conditions, it will burn.

I think it's unfair to characterize Rigeld's argument as "unthinking adherence to the rules". He very clearly used his noggin, and made a hell of a cogent argument.

Rigeld2
2007-04-16, 07:26 AM
No.
Wrong. Fire is merely oxidation. Everything oxidizes.


Um, no. I have explicitly said that the grease isn't flammable in that way - because actual grease isn't flammable in that way.
So... how would it be flammable? And, btw, not all grease is remotely flammable. Greases have come to mean something to the effect of "consisting originally of a calcium, sodium or lithium soap jelly emulsified with mineral oil." Certainly flammable at a high enough temperature, but not even remotely worth thinking about as flammable.

Tor the Fallen
2007-04-16, 07:29 AM
The noble gases refuse to oxidize. I'm pretty sure you can't get already oxidized compounds to oxidize, and I don't think gold will oxidize, either.

Rigeld2
2007-04-16, 07:31 AM
My apologies - not everything. I will amend that to almost everything. And I think Gold will oxidize, but I dont have anything to cite on that atm.

Caledonian
2007-04-16, 07:31 AM
Wrong. Fire is merely oxidation. Everything oxidizes.

No, this is wrong on multiple levels. Fire is a special kind of rapid oxidation - rusting is oxidation, but not burning.

And "everything" does not oxidize. There are plenty of things which will not react with oxygen no matter how hot they get - and certainly not under the conditions which can occur in everyday life.

I'm finished with this conversation. Enjoy yourselves, everyone.

Tor the Fallen
2007-04-16, 07:33 AM
Wrong. Fire is merely oxidation. Everything oxidizes.


So... how would it be flammable? And, btw, not all grease is remotely flammable. Greases have come to mean something to the effect of "consisting originally of a calcium, sodium or lithium soap jelly emulsified with mineral oil." Certainly flammable at a high enough temperature, but not even remotely worth thinking about as flammable.

I think grease as per the spell is animal fat. You know, like the butter or pork fat material component you used to cast the spell. Unless your mage is a vegan, in which case he may have used margarine or some other fat derived from plants.

Animal fat burns terrifically, though it requires a lot of heat and open flame. Not the sort of stuff you could light with a match, but if added to used to stoke an already conflagring conflagration, it would burn nicely.

Eldritch_Ent
2007-04-16, 07:41 AM
I'll have to agree with Caledonian here- If the Grease spell means actual Grease, then it'll burn under the same conditions Grease usually does.

I mean, the most common cause of a resturaunt burning down is actually a grease fire. The stuff isn't exactly Fire-Extinguisher material.

However, it's probably one of those things a Mage could define when first learning the spell. (Much like, say, a mage can have his Magic Missiles look like sparks, arrows, boomerangs, slappy hands...) so you might have a gnomish gadget-mage summon Machine Grease, a human summon regular old butter, an elf summon Margarine, a dwarf summoning boar lard, etc....
But I can't really think of any type of grease that doesn't burn.

In short, just ask your PC to be specific on what KIND of grease his grease spell summons, look up it's ignition conditions online, and go from there.

Tor the Fallen
2007-04-16, 07:44 AM
However, it's probably one of those things a Mage could define when first learning the spell. (Much like, say, a mage can have his Magic Missiles look like sparks, arrows, boomerangs, slappy hands...)

I mean this not as a criticism or nothing, but where is that, eh, rule, found?

Eldritch_Ent
2007-04-16, 07:51 AM
I mean this not as a criticism or nothing, but where is that, eh, rule, found?

I think it was one of those "Footnote" type entries either in the DMHB or the PsiHB saying that altering spells in superficial ways can make them more flavorful... Currently looking for it, actually.

Edit: Nope, can't find it- maybe they took it out in the switch from 3 to 3.5.... However it's not really meant for altering mechanics, it's mostly just for flavor, and the type of grease would matter- however, I'd agree that it'd take 2 rounds to set any meaningful amount of grease on any meaningful amount of fire. I'd probably assign damage to it equal to an oil fire, and have it last just as long. (AKA nonmagical fire. It does what- 1d6 a round?), even level 1 PC's have access to lamp oil and torches, so it's not really unbalancing for a low level spell to use it that way IMO.

Also,


You know, if you had to bear the weight of comma splices upon your visage, you'd look like Dorian Gray if he didn't have that nifty painting. Srsly.

Did you just Grammar-Patrol yourself for splicing your own commas?

Indon
2007-04-16, 08:11 AM
Grease of the kind created by the spell (animal fat or the like, as noted earlier) is quite flammable - when near an oven or stove producing significant temperature. I'd say small fires such as those of torches couldn't ignite it, though a Fireball (http://www.d20srd.org/srd/spells/fireball.htm) or similar intense heat would logically set it on fire.

Larrin
2007-04-16, 08:15 AM
I think that this discussion hits on a slightly deeper theme then originally intended (perhaps) which is "When will things burn in D&D" there are rules for cathching fire, mentionings of flamable items (which of course are left to the users to define) and thats about all RAW wrote. It seems to be that descision of what burns is completely up to the DM/players. Thus if DM rules that grease burns, it burns. With no support for it burning any more or less than any other burnable one has to assume you should simply follow the "cathing on fire rules" (http://www.d20srd.org/srd/environment.htm#catchingOnFire) for both the grase and those on it (perhaps ruling that each 5x5 square is a sperate patch and they need to catch fire in sequencial round, hence the whole puddle doesn't just poof up all at once). If the DM rules its not flamable (or at least not flammable enough to matter) then it doesn't burn. Everything else is houserules and Catgirl-a-cide.

Tor the Fallen
2007-04-16, 08:22 AM
I think it was one of those "Footnote" type entries either in the DMHB or the PsiHB saying that altering spells in superficial ways can make them more flavorful... Currently looking for it, actually.

Edit: Nope, can't find it- maybe they took it out in the switch from 3 to 3.5.... However it's not really meant for altering mechanics, it's mostly just for flavor, and the type of grease would matter- however, I'd agree that it'd take 2 rounds to set any meaningful amount of grease on any meaningful amount of fire. I'd probably assign damage to it equal to an oil fire, and have it last just as long. (AKA nonmagical fire. It does what- 1d6 a round?), even level 1 PC's have access to lamp oil and torches, so it's not really unbalancing for a low level spell to use it that way IMO.

Sounds 3.0.

In Player's Guide to Faerun, there's a feat called spell thematics. This gives your spells a theme like 'sphere' or 'lightning' (they give an example of summoned monsters springing from a ball you throw), increases the spellcraft to identify your spells by 4, one spell and one at each subsequent level is designated your 'thematic' spell, and is cast at +1 caster lvl. The feat doesn't affect any other spell variables.


Did you just Grammar-Patrol yourself for splicing your own commas?

With a run on sentence, no less.

Jayabalard
2007-04-16, 11:21 AM
Wrong. Fire is merely oxidation. Everything oxidizes.Fire is not merely oxidation; it's oxidation that also happens to be an exothermic reaction. Not all oxidation reactions are exothermic, nor do all elements oxidize (Even though they are no longer considered totally inert, a noble gas does not oxidize afaik).

Jayabalard
2007-04-16, 11:31 AM
Grease of the kind created by the spell (animal fat or the like, as noted earlier) is quite flammable - when near an oven or stove producing significant temperature. actually, animal fat isn't all that flammable until it is rendered, meaning the fat being liquefied and being separated from the fat solids, and even then it has to be at a fairly high temperature to ignite.

for example: take a piece of bacon, which has high surface area to the mass (ideal for ignition), and dip it fairly quickly into a fire... nothing happens. The fat is quite greasy and slippery, but not all that flammable. if you heat it up for a while and then pour it into the fire... much more flammable.

just for reference (http://drinc.ucdavis.edu/dairychem7_new.htm), the smoke point (where the oil starts to smoke/burn due to heat) of most oils is ~300-500 degrees, and the lower smoke point oils are generally caused by impurities that smoke and burn well before the oil itself does.

Ikkitosen
2007-04-16, 11:35 AM
The question is "Does Grease burn", not "does grease burn". We're not discussing the flammability of normal grease, but rather that of the spell Grease. Since most things burn under the correct conditions one can infer that the spell Grease is not meaningfully flammable, hence the existence of the 2nd level, specifically flammable version.

Penguinizer
2007-04-16, 11:39 AM
No, this is wrong on multiple levels. Fire is a special kind of rapid oxidation - rusting is oxidation, but not burning.



Rusting is slow oxidation, a slow burning. /science geek :P

But I suppose its up to houseruling.

But for the rusting, Rusting consumes oxygen in a sealed space such as a test tube with its top in water. A simple experiment to show this is to take a test tube, stick some iron wool into the bottom so it stays there. Then put it upside down into a bowl with water so that the water is at the same level in the test tube and the bowl, then leave it so that it stays up. After some time as the iron wool rusts the water level in the test tube will be higher than in the bowl. Indicatin that rusting is indeed a slow burn.

But I think that doesnt actually prove anything...

Indon
2007-04-16, 11:39 AM
actually, animal fat isn't all that flammable until it is rendered, meaning the fat being liquefied and being separated from the fat solids, and even then it has to be at a fairly high temperature to ignite.

for example: take a piece of bacon, which has high surface area to the mass (ideal for ignition), and dip it fairly quickly into a fire... nothing happens. The fat is quite greasy and slippery, but not all that flammable. if you heat it up for a while and then pour it into the fire... much more flammable.

just for reference (http://drinc.ucdavis.edu/dairychem7_new.htm), the smoke point (where the oil starts to smoke/burn due to heat) of most oils is ~300-500 degrees, and the lower smoke point oils are generally caused by impurities that smoke and burn well before the oil itself does.

Yes, my point was that modern cooking appliances such as ovens and stoves produce hundreds of degree (deg. F, not C) temperatures, allowing them to ignite fats. I then went on to say that normal fire such as from a torch wouldn't ignite the grease, but the fire from a Fireball spell (which produces heat sufficient to melt soft metals, for instance) would.

Aquillion
2007-04-16, 11:52 AM
The existence of an almost identical spell a level higher that does burn implies that Grease burns in no meaningful manner.Incendiary Slime is highly flammable; that's the purpose of the spell. It conjures some stuff that is far, far more flammable than ordinary grease, hence its higher level.

The grease spell, as described, just conjures a field of (far-less combustable, but still flammable under the right circumstances) normal grease. Like any other conjured object, it has all the properties of ordinary grease, except as stated otherwise in the spell. That means that Grease is as flammable as grease, no more and no less.

CharPixie
2007-04-16, 11:59 AM
As this discussion proves, if you want to know in depth spell mechanics or exactly how far real world physics extends into your game, ask your DM.

Jayabalard
2007-04-16, 12:08 PM
Yes, my point was that modern cooking appliances such as ovens and stoves produce hundreds of degree (deg. F, not C) temperatures, allowing them to ignite fats. I then went on to say that normal fire such as from a torch wouldn't ignite the grease, but the fire from a Fireball spell (which produces heat sufficient to melt soft metals, for instance) would.I understood, that's why I was disagreeing; just applying heat to cold fat isn't enough to ignite it.


The question is "Does Grease burn", not "does grease burn". We're not discussing the flammability of normal grease, but rather that of the spell Grease. Since most things burn under the correct conditions one can infer that the spell Grease is not meaningfully flammable, hence the existence of the 2nd level, specifically flammable version.In addition to asking about RAW, the OP is also asking about GM rulings; so as long as a GM is going to make thier ruling at least partially based on whether grease (not the spell, the stuff) burns is relevant.

my take: it wouldn't burn unless exposed to high temperatures for quite a while (to render or liquefy it), and once ignited it wouldn't burn for very long (a few seconds) since the coating is very light.

Tor the Fallen
2007-04-16, 12:11 PM
I would like to point out that Grease, unlike Web, doesn't allow for SR. This implies that the grease created isn't magical. Or something.

TheOtherMC
2007-04-16, 12:12 PM
Yes, sounds like you had fun with that. Caledonian: You raise some very useful points :smallsmile:

Well our merry band of 11(!) adventurers are hading twords a forest on the way to a port town when failing my reflex save (I am a knight after all..) A vine comes down and tries to choke me. After a long discussion about whether my damage reduction from my adamantine armor would stop it someone shoots the damn thing and it lets me go. 7 more vines lower. The new (and very hot) party wizard casts grease on them making it harder for them to grab us. A few rounds later we killed a couple and herded them into a nice 10ft cone shape for the same wizard (still very hot) to use burning hands on........we kinda forgot she put grease on them 3 rounds earlier....and that the vines were attatched to the regular trees................

Turns out it was a protected forest and we were hunted by druids for the remainder of canpaign. The bright side? We got XP for the dozens of other kilelr vines in the forest :P

Sotha_Cid
2007-04-16, 12:37 PM
The idea that you could get a level's worth of XP, if not multiple levels worth of XP, from starting a forest fire at level one, is both a hilariously bad and an AWESOME thought.

Amphimir Míriel
2007-04-16, 12:58 PM
I think it was one of those "Footnote" type entries either in the DMHB or the PsiHB saying that altering spells in superficial ways can make them more flavorful... Currently looking for it, actually.

Edit: Nope, can't find it- maybe they took it out in the switch from 3 to 3.5.... However it's not really meant for altering mechanics, it's mostly just for flavor, and the type of grease would matter- however, I'd agree that it'd take 2 rounds to set any meaningful amount of grease on any meaningful amount of fire. I'd probably assign damage to it equal to an oil fire, and have it last just as long. (AKA nonmagical fire. It does what- 1d6 a round?), even level 1 PC's have access to lamp oil and torches, so it's not really unbalancing for a low level spell to use it that way IMO.


Actually it's in the DMG. I can't really give you the actual page since I don't have the book with me at this moment...

But indeed it is cited as a way to make individual spellcasters "unique"... However this is meant (IMHO) as a way to make purely cosmetic changes to spells, and not something that actually alters the way it works.

Edit: Although the same example mentions "Cold Balls" instead of fireballs... so maybe a gnomish mage can summon axle grease instead of pork fat

But really, I am more interested in creating a first level "detergent" spell, to cancel out those pesky grease casting mages...

blacksabre
2007-04-16, 03:09 PM
Grease is not an acceraant until it is heated above 315 degress, thats when carbon is released as a gas, and thuus flamable..

grease fires occur in kitchens when the grease is heated and placed on a hot surface in which it rapid boils, causing a huge relaes of carbon..add open flame and you have a fire ball..

Teloric
2007-04-16, 03:25 PM
Grease makes no mention of whether it is flammable or not. If it were, it would probably say so since there is a precedent for this (see the Web spell). Generally speaking, you should not assume that something has a property or characteristic unless it is specifically stated, particularly where spells are involved. So, going strictly by the spell description, we cannot assume that Grease is flammable.

Likewise, you cannot assume that your conjured Grease is something flammable like animal fat. There are many types of Grease, some that aren't very likely to burn at all, and some that are certainly more flammable than animal fat. Teflon grease, for example, is very resistant to burning.

Having said all this, if I were DMing, I would probably give you a chance that it will burn, depending on how you are trying to light it. The hotter your flame source, the more likely I'd allow it. I'd give a tinder twig a 10% chance, and a torch a 50-50 chance. It would never be 100% certain though...

Aquillion
2007-04-16, 04:49 PM
Grease makes no mention of whether it is flammable or not. If it were, it would probably say so since there is a precedent for this (see the Web spell). Generally speaking, you should not assume that something has a property or characteristic unless it is specifically stated, particularly where spells are involved. So, going strictly by the spell description, we cannot assume that Grease is flammable.Spiderwebs are not the slightest bit flammable in real life. They simply aren't. That is mentioned there, in other words, because it's a deviation from the normal properties of spiderwebs; if it weren't mentioned, they wouldn't burn because they're spiderwebs and spiderwebs do not burn.

Absent something in the spell description stating otherwise, you get exactly what is named in the spell. Create Water conjures normal water that can put out fires, soak clothes, and do everything else water does, even though none of that is mentioned in the spell; Grease produces normal grease that ignites under any circumstances that would normally ignite grease.

A more salient point: Nowhere in the Wall of Stone spell description does it say that the wall conjured by that spell blocks movement. By your logic, would it be a mistake to assume that property?

Ikkitosen
2007-04-16, 05:01 PM
Spiderwebs are not the slightest bit flammable in real life. They simply aren't. That is mentioned there, in other words, because it's a deviation from the normal properties of spiderwebs; if it weren't mentioned, they wouldn't burn because they're spiderwebs and spiderwebs do not burn.

Absent something in the spell description stating otherwise, you get exactly what is named in the spell. Create Water conjures normal water that can put out fires, soak clothes, and do everything else water does, even though none of that is mentioned in the spell; Grease produces normal grease that ignites under any circumstances that would normally ignite grease.

A more salient point: Nowhere in the Wall of Stone spell description does it say that the wall conjured by that spell blocks movement. By your logic, would it be a mistake to assume that property?

No, but there are no types of stone that don't block movememnt. There are types of grease that don't (meaningfully) burn, so you're making an assumption if you say it burns.

Merlin the Tuna
2007-04-16, 05:03 PM
Grease produces normal grease that ignites under any circumstances that would normally ignite grease.There is no such thing as "normal grease." Grease is a term which describes anything slippery, from oils to jello to teflon. That the material component is animal fat does not mean that the spell creates animal fat. Fireball doesn't eject flaming bat poop in every direction, Glitterdust doesn't have the same effect as hurling ground mica up into the air, Alarm doesn't create magical silver bells hanging from silver wires, and Cone of Cold shoots cold, not glass. You're simply reading far too much into the flavor text, and now you're venturing into the realm of "The rules don't say I can't."

Fax Celestis
2007-04-16, 05:05 PM
Grease of the kind created by the spell (animal fat or the like, as noted earlier) is quite flammable - when near an oven or stove producing significant temperature. I'd say small fires such as those of torches couldn't ignite it, though a Fireball (http://www.d20srd.org/srd/spells/fireball.htm) or similar intense heat would logically set it on fire.

...the spell doesn't create cooking grease or animal fat. It creates a slippery effect--which Conjuration (Creation) can do according to RAW:
Each conjuration spell belongs to one of five subschools. Conjurations bring manifestations of objects, creatures, or some form of energy to you (the summoning subschool), actually transport creatures from another plane of existence to your plane (calling), heal (healing), transport creatures or objects over great distances (teleportation), or create objects or effects on the spot (creation).

If it created actual, honest-to-god-burninating-the-peasants grease, it'd be Duration: Instantaneous instead of Duration: 1 round/level.

Since it is not a Conjuration (Summoning) spell, we can understand that it is not summoning Paragon Grease from the Elemental Demiplane of Cooking Fluids. Instead, it is a Conjuration (Creation) spell, which means it's creating an effect: in this case, a slime that makes people trip.

Nowhere in the spell description does it say it is actually creating flammable grease, nor does it state that it creates actual grease. It creates an effect that causes people within the area to trip. I could rename the spell to banana peel field, zone of clumsiness, or slippery frogslime of tripping and looking ridiculous and not change the mechanics of it at all (up to and including the material component) and still have it make complete sense.

So, no, grease, by RAW, is not flammable.

Indon
2007-04-16, 05:32 PM
...the spell doesn't create cooking grease or animal fat. It creates a slippery effect--which Conjuration (Creation) can do according to RAW:


On the one hand, that is a very good point about the spell duration; normal grease wouldn't just magick itself away when the spell duration wears off.

On the other hand, the spell seems to say quite plainly that it 'covers a solid surface in a layer of slippery grease'. This grease exists by act of magic; magic goes away, so does the grease, but is this grease otherwise magical?

Fax Celestis
2007-04-16, 05:43 PM
For this I turn you once again to the description of the Conjuration school:


If the spell has a duration other than instantaneous, magic holds the creation together, and when the spell ends, the conjured creature or object vanishes without a trace. If the spell has an instantaneous duration, the created object or creature is merely assembled through magic. It lasts indefinitely and does not depend on magic for its existence.

The Pink Ninja
2007-04-16, 05:48 PM
If it doesn't say so in the book it doesn't.

But if you think it's cool allow it anyway.

Merlin the Tuna
2007-04-16, 06:25 PM
On the other hand, the spell seems to say quite plainly that it 'covers a solid surface in a layer of slippery grease'.On the other hand, it says quite plainly that it 'covers a solid surface in a layer of slippery grease.' There's no mention of 'slippery, flammable grease' nor of 'slippery grease made of animal fat.' Given that they're using an adjective to denote that the grease is slippery -- a requirement to be called grease in the first place -- it seems a fair assumption that, were it flammable, they would note that as well, as it isn't a characteristic of all grease.

belboz
2007-04-16, 07:59 PM
Anyway, for a first-level spell, grease is powerful enough just for battlefield control. Why make it even stronger?

WildBill
2007-04-16, 09:35 PM
My chem geekness requires that this be posted.
Regarding the definition of fire and oxidation, fire is oxidation occuring in the vapor phase (meaning the vapor pressure of the burning substance is high enough for it to feed the combustion) which is why metal fires are so absurdly hot (like burning iron or aluminum).
Not everything will burn (or oxidize), things in there highest oxidation state will not burn and will in fact help put out fires, like CO2 or water. Fluorine gas will not burn as it will actually burn oxygen. And helium and neon and have not yet been made to react with fluorine or oxygen, although the remainder of the nobel gasses have formed compounds with fluorine, and all but argon have formed oxides.
And gold will oxidize. A solution of 1 part concentrated nitric acid and 3 parts concentrated hydrochloric acid (known as aqua regia because of this property) will dissolve gold. The nitric acid will oxidize the gold, and the HCl will make the Au3+ form a soluble chloride.
/chem geek

Collin152
2007-04-16, 10:54 PM
On the other hand, it says quite plainly that it 'covers a solid surface in a layer of slippery grease.' There's no mention of 'slippery, flammable grease' nor of 'slippery grease made of animal fat.' Given that they're using an adjective to denote that the grease is slippery -- a requirement to be called grease in the first place -- it seems a fair assumption that, were it flammable, they would note that as well, as it isn't a characteristic of all grease.
Show me a grease that can in no ways burn, and I'l agree. But until I see said grease being dangled inches above Lava and return un-burninated, I say it works.

It does a measly 1d6 per round and would probably end the spell, but it works.

belboz
2007-04-17, 01:13 AM
The question isn't just whether it can burn (if, say, placed in lava), but whether it's capable of self-sustaining flame. Usually, when people say a material is "flammable", that's what they mean--not just that it can be oxidized, but that the oxidization produces enough energy to spread.

Lots of grease is not, I think, flammable in that sense. Plus, it also needs to have an ignition point lower than the temperature of whatever you're lighting it with.

AtomicKitKat
2007-04-17, 03:27 AM
So what happens if 3 mages cast, one after another, Grease, Flaming Sphere, and Create Water? ;D

Last_resort_33
2007-04-17, 04:19 AM
What if you were to use creation to create a big bucket of coal, can that also not catch fire? It is a Conjuration(Creation) spell, the effects wear off... what's the difference? It takes quite a bit to get raw coal burning as well, but when it does burn, it burns very nicely.

Grease DOES catch fire... I assure you of that...

*looks over the thread* There appear to be a lot of corpses here. *rolls one over* looks like catgirls...

AtomicKitKat
2007-04-17, 07:43 AM
I remember Aqua Regia. First time I heard of it was some series of books I borrowed from the library, involving a boat named "Amanda"(?), and a bunch of kids, including one boy who whined a bit about his name ending in "an" and people in his school teasing him by stretching it to "-anne" and making it into a girl's name. :P

Indon
2007-04-17, 08:53 AM
Anyway, for a first-level spell, grease is powerful enough just for battlefield control. Why make it even stronger?

Well, incinerating the Grease (such as from a Fireball spell) would probably consume it in one or two rounds, if the DM doesn't rule that the grease layer is thin enough to burn up immediately.

So it's not neccessarily stronger if it's on fire.

Merlin the Tuna
2007-04-17, 10:08 AM
Show me a grease that can in no ways burn, and I'l agree.Already been done. (http://en.wikipedia.org/wiki/Teflon) Alternatively, a sheet of ice. You can go to the volcano for that one by yourself if you like, but I'm pretty sure that won't ignite.

Amphimir Míriel
2007-04-17, 11:15 AM
A lot of the responses on this thread are focused on Grease + Fire being used as a "Flaming Death" kind of effect...

As a DM, I would rule that this type of usage wouldnt work (Grease is already powerful enough with what it does)

However, by the same rationale, I would perhaps rule that a Flaming Sphere, Burning Hands or something similar would "burn" the thin coating of grease enough to negate the slippery effect in the area of effect of the fire spell...

Of course, doing this on a wooden floor might be a bad idea...

Tor the Fallen
2007-04-17, 11:18 AM
Wood, by RAW, needs to take at least 6 damage or more by fire to be damaged.

"Polytetrafluoroethylene (PTFE) is a synthetic fluoropolymer." Now how is a wizard conjuring that?\

OzymandiasVolt
2007-04-17, 11:40 AM
omg, a spell doesn't say that its effect DOESN'T do something! Hey, you know that spell, fireball? Nowhere in the description does it say that it DOESN'T create a spray of platinum coins worth 200,000gp when it ends. So obviously it does. :P

Indon
2007-04-17, 11:44 AM
omg, a spell doesn't say that its effect DOESN'T do something! Hey, you know that spell, fireball? Nowhere in the description does it say that it DOESN'T create a spray of platinum coins worth 200,000gp when it ends. So obviously it does. :P

If only intense fire really DID create money in real life.

A better example would be Fireball evaporating water. I'm pretty sure it doesn't say Fireball can evaporate any quantity of water, but fire, being very hot, can generally evaporate water. So if you shoot a Fireball at water, you can reasonably claim that that Fireball will evaporate some, or all if there's not much, of that water.

Jayabalard
2007-04-17, 12:07 PM
If only intense fire really DID create money in real life.

A better example would be Fireball evaporating water. I'm pretty sure it doesn't say Fireball can evaporate any quantity of water, but fire, being very hot, can generally evaporate water. So if you shoot a Fireball at water, you can reasonably claim that that Fireball will evaporate some, or all if there's not much, of that water.Fire does not evaporate water; heat does; it takes time for radiant heat to raise the temperature of water to the point that it will evaporate, and since a fireball is pretty much instantaneous, it doesn't have time to evaporate any of it.

along the same lines...

If only intense fire really did set fire to a conjured slippery effect... or even all types of physical grease.

CharPixie
2007-04-17, 12:14 PM
With high ranks in Knowledge(Chemistry).

mauslin
2007-04-17, 06:56 PM
Um, I'm very much a newbie here, and I have a few questions.

If one was to declare that Grease was completely fireproof, then it would mean that you could use it to put out fires right?
Would that also mean that by casting Grease on something, you could prevent it from catching on fire in the first place?
Would casting it on a Fire Elemental cause damage?
Could it be used to put out things that water can't, like naphtha or sodium metal?

If the Grease spell is flammable, but burns up so quickly that it causes minimal damage, could you use a spell like burning hands to remove an existing Grease spell?
Could you use a Grease spell and a burning hands spell like a fuse for a bomb (i.e. there's a keg of smoke-powder across the room. First cast a line of Grease from you to the keg. Then light your side of the Grease line with burning hands. Imagine the rest.)

Finally, if Grease is in fact flammable, could you it to heal/enhance a fire elemental?

DaMullet
2007-04-17, 07:29 PM
That's why it's easier to say, "No. Siddown."

If you make all those assumptions, you end up with worse problems.

Indon
2007-04-17, 07:35 PM
Fire does not evaporate water; heat does; it takes time for radiant heat to raise the temperature of water to the point that it will evaporate, and since a fireball is pretty much instantaneous, it doesn't have time to evaporate any of it.


Anything that can melt gold (as per Fireball's description), produces sufficient heat to evaporate at least _some_ water. Wouldn't you agree?

LeeMon
2007-04-17, 07:39 PM
Can you believe the first D&D campaign I ever DM'd ended over an argument on this very question?

One of the first fights resulted from an owlbear being the target of a Grease Spell and a Burning Hands spell, followed by much high-fives amongst the players.

Then I said it didn't do what they think it did.

My reasoning was similar to others: I interpret "grease" as a slippery substance or lubricant, nothing more. More importantly, most spells that might make something catch on fire say so (see Burning Hands, Fireball). In the absence of a rule saying what would happen to the grease when it caught fire, I felt it was reasonable to conclude that it had no such effect. The resulting arguments broke up the group.

Of course, that was years ago... I had never even cracked open the DMG (I only had the PHB; I was using monster stats in the adventure and assigning XP according to how fast I wanted the group to level). Nowadays, I still believe that ruling is correct, particularly since there's a 2nd level spell that is identical save for explicit rules regarding flammability. I'd also specifically state my interpretation that the only physical artifact of the conjuration is the slipperiness, and no other physical properties that might potentially be applied to a real physical item that is also named "grease". You might as well try to thread the bead from Fireball.

That said, nowadays I'd also not get involved in a fight with the players just to save AN OWLBEAR from taking 1d6 extra damage; I'd let it burn. Players who can't accept "This is how I'm ruling it, we can discuss it for next time when the session is done, can we please continue?" don't do well at my table, though. I'd let it slide, but they might catch fire themselves down the road when an enemy mage knows their cool trick. But it would only happen once. :)

P.S. I'd use the Underwater Combat section of the SRD to adjucate fireball hitting water, specifically the section stating "The surface of a body of water blocks line of effect for any fire spell."

Matthew
2007-04-17, 08:37 PM
That doesn't sound like it was a problem 'in the game', so much as 'out of it'. If a group is going to bust up over something like that, it probably wasn't meant to be.

Curmudgeon
2007-04-17, 09:05 PM
Grease is only symptomatic of the problem of players trying to create widespread damage with simple objects. The most common example I've seen is players attempting to use wine as an accelerant (because it contains alcohol, you see). They get incensed when I tell them that it puts the fire out instead of enlarging it. Even distilled spirits like whiskey are still mostly water.

Mythbusters showed that a lit cigarette can't ignite a pool of gasoline. It takes a vapor with the right mix of gasoline fumes and air (oxygen) and a draft through the cigarette to make it red hot to be able to start a gasoline fire.

If it's that difficult to get a volatile fuel to ignite, it doesn't seem reasonable that Grease will burn in any useful way.

Jayabalard
2007-04-18, 08:33 AM
Anything that can melt gold (as per Fireball's description), produces sufficient heat to evaporate at least _some_ water. Wouldn't you agree?not necessarily; gold has a much lower specific heat than water, 0.1291 vs 4.1813; the difference in specific heat is a factor of 32x, while the difference in the boiling point of water vs the melting point of gold is only a factor of 1.064 or so. If you have equal masses of gold and water, and the water and gold both start at ~25C, the gold will melt and liquefy before the water has absorbed enough heat to reach it's boiling point; the water only reaches ~57 C, which is well under the boiling point, while the gold has reached ~1064 (it's melting point) C.

Assuming that the specific heat of gold as a liquid is the same as the specific heat as a solid (which I'm not sure of) if you drop the starting temperature low enough (less than 13 C) and then subject an equal mass of gold and water to the same heat, the gold will reach the boiling point (~2800C), slightly before before the water reaches it's boiling point (100C)...

So a fireball is not necessarily any more effective at evaporating water than sitting it in sunlight or just leaving it in the open air.


Grease is only symptomatic of the problem of players trying to create widespread damage with simple objects. The most common example I've seen is players attempting to use wine as an accelerant (because it contains alcohol, you see). They get incensed when I tell them that it puts the fire out instead of enlarging it. Even distilled spirits like whiskey are still mostly water.Anything over 100 proof is mostly alchohol, not mostly water... but it still contains a lot of water.

wine though, is certainly mostly water... it might burn a little but it's going to put the fire out, and even the parts that ignite aren't going to generate much heat as alcohol burns at a pretty low temperature.


Mythbusters showed that a lit cigarette can't ignite a pool of gasoline. It takes a vapor with the right mix of gasoline fumes and air (oxygen) and a draft through the cigarette to make it red hot to be able to start a gasoline fire.actually... the limitation on the cigarette lighting the gas is the temperature that it burns at as opposed to the ignition temperature of the gasoline. It can do it while actively being smoked but if you just throw it in it doesn't have the heat.

"A cigarette has the potential to light a pool of gasoline but just doesn't have enough sustained heat. Gas ignites between 500 °F and 540 °F, the cigarette at its hottest was between 450 °F and 500 °F but only when it was actually being smoked. An ignition is very improbable."

A torch on the other hand, burns at a much higher temperature... it wouldn't have any problem igniting it.

Tor the Fallen
2007-04-18, 08:38 AM
What's the specific density of gold v. water, though?

Jayabalard
2007-04-18, 08:55 AM
What's the specific density of gold v. water, though?Do you mean specific gravity?

in any case, I'm not sure how it relates.

Indon
2007-04-18, 09:06 AM
Well, I have learned of one thing Fireball can definitely evaporate: Catgirls.

And Curmudgeon; in my games, I dubbed that urge "MacGyver syndrome".

Player: "I take a piece of chewing gum and a jury-rigged Tesla coil, put them together and cast Color Spray on it. What do I kill?"

Me: *sigh*

Tor the Fallen
2007-04-18, 09:12 AM
Do you mean specific gravity?

in any case, I'm not sure how it relates.

Well, if you have a bucket of water and a bucket of gold, there's far more gold in it, as gold is denser that water. How much, I don't know, but if you have more of something, it's harder to heat up. If you turn a gold coin to liquid, how much water can you turn to gas with the same amount of heat?
And are you factoring in the fact that the energy required to heat something from X to Y, and from Y to Z is nonlinear?

Jayabalard
2007-04-18, 09:36 AM
Certainly, gold is more dense than water but you should note that above I said mass... So the relative density isn't really important.

Also note that this is to show why I disagree with the statement "Anything that can melt gold (as per Fireball's description), produces sufficient heat to evaporate at least _some_ water." ... it's sufficient to show that there are cases where the amount of heat needed to melt gold will not to boil water.

as for being non-linear... I'm not sure what you mean. (catgirl killing continues) The applicable formula relating temperature change to heat applied is Q = m c ΔT.

Q = the energy added or removed
m = mass
c = heat capacity (aka: specific heat capacity (http://en.wikipedia.org/wiki/Specific_heat_capacity))
ΔT = the change in temperature.

In my example, you have 2 objects (one gold and one water), with the same mass, subjected to the same heat energy (the same fireball), then you have
Gold: Qg = mg cg ΔTg
Water: Qw = mw cw ΔTw

Qg = Qw (same energy allied to both)
so: mg cg ΔTg = mw cw ΔTw.

and mg =mw ; mw != 0;
so: cg ΔTg = cw ΔTw.

substitute in known data from tables, and solve for ΔTw
so: ΔTw = ( 0.1291 * ΔTg )/ 4.1813

Assume that you are going to melt the gold, as per the fireball spell
ΔTg ~= 1064 (melting point of gold)

so ΔTw = ( 0.1291 * 1064 )/ 4.1813 = 32.85 C.

Tor the Fallen
2007-04-18, 09:43 AM
Mass matters, because if you have gold in any appreciable quantity (say, a treasure chest of gold coins), there are more molecules of gold, if the chest was instead filled with water. Right?

So in the instances an adventurer is likely to run into gold (which would likely be less than 24k), it will be of quantities such that if it were water he was fireballing (rather than gold), the difference in respective mass would be appreciable.

Re energy for heating:

If you want to heat something from 1 degree to 2 degrees, it takes X amount of energy, but from two to three degrees, it takes a little more than X, say X+0.1, and so on. Or is this not the case?

Jayabalard
2007-04-18, 10:12 AM
Mass matters, because if you have gold in any appreciable quantity (say, a treasure chest of gold coins), there are more molecules of gold, if the chest was instead filled with water. Right?

So in the instances an adventurer is likely to run into gold (which would likely be less than 24k), it will be of quantities such that if it were water he was fireballing (rather than gold), the difference in respective mass would be appreciable.]Gold isn't molecular; Gold atoms are much more massive than oxygen or hydrogen, or water; one gold atom is more than 10x as massive as a water molecule; equal masses of gold and water have far fewer gold atoms than water molecules.

None of that has anything to do with whether "Anything that can melt gold (as per Fireball's description), produces sufficient heat to evaporate at least _some_ water." ... showing a single case where you can melt (and possibly boil) gold without boiling water is sufficient.


Re energy for heating:

If you want to heat something from 1 degree to 2 degrees, it takes X amount of energy, but from two to three degrees, it takes a little more than X, say X+0.1, and so on. Or is this not the case?No, generally this is not the case. I believe there are exceptions once you start dealing with plasmas (extremely high heat), objects near absolute 0, and gases in closed containers where changes in temperature change the density ... but for the most part, specific heat is a constant for a particular material in a particular state.

Tor the Fallen
2007-04-18, 07:14 PM
Ack, my response was never posted. Lemme try again.


]Gold isn't molecular; Gold atoms are much more massive than oxygen or hydrogen, or water; one gold atom is more than 10x as massive as a water molecule; equal masses of gold and water have far fewer gold atoms than water molecules.

And water isn't atomic. More units of gold? More mass. Equal volumes of gold and water, the gold will have more mass, as there are more... pieces of gold. There's more gold.


None of that has anything to do with whether "Anything that can melt gold (as per Fireball's description), produces sufficient heat to evaporate at least _some_ water." ... showing a single case where you can melt (and possibly boil) gold without boiling water is sufficient.

Well, as long as we're hypothesis testing a post that was obviously not meant to be read verbatim as a serious scientific hypothesis and given that we're talking about magic, and that your logic is contingent on literal interpretation of what was posted, he said evaporation. :smallwink:

When a fireball goes off over water, it will raise the air temp, thus raising the amount of water the air can hold, which will evaporate water.

Furthermore, your test doesn't quite work, as the fireball description isn't "given equal masses water and gold, the gold melts and nothing happens to the water." The question here is what a fireball does to water, the assumption being if it can melt metal, it can probably evaporate (liquid) water. Showing a single case that involves boiling gold but not water is insufficient- you assume that the amount of masses are equal. If you have 30x the mass of gold than water, for instance, then the water will evaporate. We have two unknowns: the mass of the material being heated, and the amount of heat. Your solution of equating mass, while elegant, only works for a couple cases.

Allow me to try an elucidate.

It's "it can melt metals with low melting points, such as lead, gold, copper, silver, and bronze." We assume that this involves appreciable quantities of metal- a bronze statue, a pile of gold, silverware, etc.

Let's say, for simplicity's sake, we have a puddle of solid gold, and a puddle of liquid water, both at 25 degrees C. Both have identical dimensions, which gives them identical volume. Both rest on the same substrate, all other variables (besides mass) etc, are constant.

A fireball, by RAW, may melt the gold. Looks like DM discretion. For the sake of this argument, the fireball melts the gold. The puddle of gold is ~20x as dense as the water, which would mean that there is a great deal more gold than water. Which means more mass. Which means that based on DM ruling of what melts, a fireball adds a more or less arbitrary amount of energy to some soft metal, which then melts. As the energy is more or less arbitrary (does the fireball merely fuse a handful of gold coins or turn the torso of the golden statue to molten gold?), a more or less amount of water may be boiled.


That wasn't very clear, but I think you'll get me.


No, generally this is not the case. I believe there are exceptions once you start dealing with plasmas (extremely high heat), objects near absolute 0, and gases in closed containers where changes in temperature change the density ... but for the most part, specific heat is a constant for a particular material in a particular state.

Ah, thanks for the correction.

Teloric
2007-04-18, 07:23 PM
And yet another catgirl dies...

Amphimir Míriel
2007-04-18, 07:43 PM
...The applicable formula relating temperature change to heat applied is Q = m c ΔT.

Q = the energy added or removed
m = mass
c = heat capacity (aka: specific heat capacity (http://en.wikipedia.org/wiki/Specific_heat_capacity))
ΔT = the change in temperature.

In my example, you have 2 objects (one gold and one water), with the same mass, subjected to the same heat energy (the same fireball), then you have
Gold: Qg = mg cg ΔTg
Water: Qw = mw cw ΔTw

Qg = Qw (same energy allied to both)
so: mg cg ΔTg = mw cw ΔTw.

and mg =mw ; mw != 0;
so: cg ΔTg = cw ΔTw.

substitute in known data from tables, and solve for ΔTw
so: ΔTw = ( 0.1291 * ΔTg )/ 4.1813

Assume that you are going to melt the gold, as per the fireball spell
ΔTg ~= 1064 (melting point of gold)

so ΔTw = ( 0.1291 * 1064 )/ 4.1813 = 32.85 C.


And yet another catgirl dies...

No Teloric, Jayabalard has seemingly commited catgirl genocide...

-

Now seriously guys, isnt this discussion a tad silly?

Indon
2007-04-18, 09:36 PM
Hey, I'm learning loads about thermodynamics, catgirls be damned (to Fireball hell, perhaps).

Vik
2007-04-19, 04:44 AM
]No, generally this is not the case. I believe there are exceptions once you start dealing with plasmas (extremely high heat), objects near absolute 0, and gases in closed containers where changes in temperature change the density ... but for the most part, specific heat is a constant for a particular material in a particular state.Sorry, but specific heat is temperature-dependant for solids, that's the Dulong's and Petit's law. At very high temperatures, it's nearly constant, but at very low temperatures there is a dependance in T^3.

Edit : also, a fireball will certainly rise the temperature of the water in surface first, evaporating it way before heating the complete mass.