Prestidigitation Question

[Kerilstrasz]

With prestidigitation you can chill or warm an inanimate object of size blah blah blah..

lets say i hold a spoon. And cast Prestidigitation to chill it or warm it..
i assume that it doesn't have a large range of temperature change.. lets say 5C for lower and 45C for higher? (a metal bar under the summer sun can easilly reach 65-90 degrees)

My question is.. this temperature change happens at once or it slowly starts to change temperature ??

The spell says instantaneous so i tend to choose the former.

The thing is..
The is a door with a lock on it. I touch the lock, and cast Prestidigitation to change its temperature fast from 10 to 50C.
after like 10-20 castings the lock will break of fatique... or at best will loose so much integrity that with a hard knock will break.

Is this a thing ??
I mean.. it is not RAI.. but.. it can happen if your DM is in physics.. shouldn't it?

[Ninja_Prawn]

Real world physics is suspended in the land of D&D!

As a DM, I'd be hesitant about setting a precedent of "if it works IRL, it works in-game", on the other hand it is clever and I'd like to reward it.

I guess, if you started wrecking everyone's locks, there would be legal consequences, and important locks would start being upgraded to magical ones. Or even non-metal locks.

And personally, I wouldn't let Prestidigitation to go up to 50. You can burn someone with that, and the spell shouldn't be dealing damage.

[Giant2005]

Firstly, I wouldn't give Prestidigitation such a massive range. I'd allow it to cool or warm something by 5-10 degrees, not have it set a temperature at a point like you seem to be suggesting. For example, you can't just touch something that is 100 degrees and immediately cool it to 5 degrees, instead you can make it 5 degrees cooler and drop it to 95 degrees.
Secondly, the Combining Magical Effects section of the PHB (Page 206) prevents a target from being effected by the same spell twice with overlapping durations. So even if Prestidigitation could have such a drastic effect on the temperature, you couldn't just keep spamming it over and over in such a short time to effect the object's integrity.

[1Forge]

You said its instantanious? then I would rule it cools at the same rate, meaning as soon as you try to re-apply you'd be back to square one. Also the spell your thinking of is "Heat Metal" I think its a second level spell I'd say becuse prestidigitation is a cantrip it has a limited range of power, like a cap that keeps you from filling a 5 by 5 cube with so many sparks it looks like fire, or flavor up a food so much it's like a drug. I know thats not the letter of the law ruling but I think it follows the spirit of the law.

You could probobly use that to prank your fellow adventurers though... The barbarian looks around quizzically when his greading glasses start flashing in temperatur, first warm then cold, he puts them on and suddenly they twitch! He leaps back telling the paladin it's possessed; you sit back trying to hold your laughter as the barbarian and paladin roll initiative and start wailing on the "possesed" pair of glasses.:smallbiggrin:

[Areinu]

I would let effects stack, but the further "magical" temperature gets from "natural" the lower the effect is. So first time you might have heated your tea by 10 degree, but next time it will give you only 3, and next time only 1, then the change would be so insignificant that natural cooling would be faster.

And even without that before lock would get so hot that it would break easily it would be too hot to touch anyway. Melting point of iron is around 1500 C, so good luck to your wizard trying to touch it around 200C, which would still be too cool to easily break. Did you ever iron your clothes? The iron gets pretty hot just to iron the clothes. Try breaking the iron part of iron then. Not easy I assume. And try touching it... No, don't. It will have consequences.

[Ninja_Prawn]

lock would get so hot that it would break easily it would be too hot to touch anyway. Melting point of iron is around 1500 C, so good luck to your wizard trying to touch it around 200C, which would still be too cool to easily break.

Nitpick: the OP never claimed to be melting the lock. They want to weaken it through rapid heating and cooling, which introduces thermal fatigue, enabling you to break the metal manually.

And I believe most locks, even in medieval settings, would be brass (or at least some manner of copper-alloy) rather than iron. Not that it really matters.

[Troacctid]

You could probobly use that to prank your fellow adventurers though... The barbarian looks around quizzically when his greading glasses start flashing in temperatur, first warm then cold, he puts them on and suddenly they twitch! He leaps back telling the paladin it's possessed; you sit back trying to hold your laughter as the barbarian and paladin roll initiative and start wailing on the "possesed" pair of glasses.:smallbiggrin:

I mean, it does have verbal and somatic components, so he would see you waving your arms and shouting "Presto!" while this is happening.

[Areinu]

Nitpick: the OP never claimed to be melting the lock. They want to weaken it through rapid heating and cooling, which introduces thermal fatigue, enabling you to break the metal manually.

And I believe most locks, even in medieval settings, would be brass (or at least some manner of copper-alloy) rather than iron. Not that it really matters.

Ah, sorry, my mistake. Well, the equipment is tested by rapidly changing temperature by more than 15 degrees per minute, so let's just keep prestidigitation below that.

Or, since it's magic, it can change the temperature that the item emits, not the temperature the item has. Just like light makes items emit light, even though there's no source of light, the prestidigitation can make items emit heat/breeze, while not changing it's physical properties.

Also, even if the item would crack from rapid cooling and heating it would take a lot of time and casts. 20 times is 20 rounds, so 2 minutes. Let's say that wizard goes for a minute cooling and heating the lock to make it break... When impatient half-orc barbarian next to him just decides enough is enough and smashes lock with his hammer. Probably much more efficient and quick.

[Ninja_Prawn]

Also, even if the item would crack from rapid cooling and heating it would take a lot of time and casts. 20 times is 20 rounds, so 2 minutes. Let's say that wizard goes for a minute cooling and heating the lock to make it break... When impatient half-orc barbarian next to him just decides enough is enough and smashes lock with his hammer. Probably much more efficient and quick.

Yeah, this is very true. At the end of the day, Thieves' Tools would be much quicker (and would leave the lock intact). Brute force is often a good alternative. The Knock spell is much more reliable.

This Prestidigitation trick, if it's allowed, is only going to be useful in a few niche cases.

[Flashy]

Let's say that wizard goes for a minute cooling and heating the lock to make it break... When impatient half-orc barbarian next to him just decides enough is enough and smashes lock with his hammer. Probably much more efficient and quick.

Pretty much this. I'd be inclined to allow it simply because it's a really circuitous and time consuming way to solve a problem with three or four way easier solutions.

[1Forge]

I mean, it does have verbal and somatic components, so he would see you waving your arms and shouting "Presto!" while this is happening.

With the barbarians perception? Naw you could just claim your doing the halfling dance of the spring or something. Or bluff and claim you'r trying to master new spells.

[1Forge]

Nitpick: the OP never claimed to be melting the lock. They want to weaken it through rapid heating and cooling, which introduces thermal fatigue, enabling you to break the metal manually.

And I believe most locks, even in medieval settings, would be brass (or at least some manner of copper-alloy) rather than iron. Not that it really matters.

BTW I am blacksmith IRL and the energy required to temper that handle would be more then presdigidation, plus with the rate of cooling the most you could do is anneal the handle (assuming you could reach those themperatures) which would take forever. You could speed up the cooling with water, but thats noisy and less effective then the half-orc ripping off the lock.

So really this wouldnt be possible with presdigidation, and even if it was it would take waaay to long and be waaay to noisy to make sense.

[Yagyujubei]

BTW I am blacksmith IRL and the energy required to temper that handle would be more then presdigidation, plus with the rate of cooling the most you could do is anneal the handle (assuming you could reach those themperatures) which would take forever. You could speed up the cooling with water, but thats noisy and less effective then the half-orc ripping off the lock.

So really this wouldnt be possible with presdigidation, and even if it was it would take waaay to long and be waaay to noisy to make sense.

i think you're missing the meat of what the OP was proposing. you arent waiting any natural amount of time for the temp change to take place.

say you rule that prestidigitation can alter the temperature of an object by 50 degrees. and then that because the duration of the spell is instant, that temperature change is instant.

so now you go up to a metal lock, and cast to raise its temp by 50 degrees instantly, then cast to lower it's temperature by 50 degrees instantly a few seconds later. Repeat this 30 times over the next three minutes and you will surely have weakened the integrity of at least the thinner more fine parts of the lock. such a large fluctuation in temp in such a small amount of time is nothing to sneeze at.

think of it in terms of water, say you have it at room temperature and cast the spell, you could take it to boiling or freezing instantly and then back to normal a second later.

edit: also just for the record, im with others in saying it's way more trouble than it's worth.

[1Forge]

i think you're missing the meat of what the OP was proposing. you arent waiting any natural amount of time for the temp change to take place.

say you rule that prestidigitation can alter the temperature of an object by 50 degrees. and then that because the duration of the spell is instant, that temperature change is instant.

so now you go up to a metal lock, and cast to raise its temp by 50 degrees instantly, then cast to lower it's temperature by 50 degrees instantly a few seconds later. Repeat this 30 times over the next three minutes and you will surely have weakened the integrity of at least the thinner more fine parts of the lock. such a large fluctuation in temp in such a small amount of time is nothing to sneeze at.

think of it in terms of water, say you have it at room temperature and cast the spell, you could take it to boiling or freezing instantly and then back to normal a second later.

edit: also just for the record, im with others in saying it's way more trouble than it's worth.

ahh but I would rule that it dosent stack, theres already a spell "heat metal" that does that, i would just say you raise the temp to that roof then stop. Its not RAW but i think it followes the spirit of the law. Besides it dosent say that the temperature lingers it could cool instantly to regular temperature then when you cast it again you'd be back at square one, the spells wouldnt be overlapping they'd be instantly after one another.

[Inevitability]

And personally, I wouldn't let Prestidigitation to go up to 50. You can burn someone with that, and the spell shouldn't be dealing damage.

Is every minor burn equal to a point of damage, though? I once burned my finger when I touched a hot frying pan; did the minor blister it got me equal a lost hit point? If I had burned a few other fingers, too, would I have collapsed on the ground; mortally wounded? I think not.

[Yagyujubei]

ahh but I would rule that it dosent stack, theres already a spell "heat metal" that does that, i would just say you raise the temp to that roof then stop. Its not RAW but i think it followes the spirit of the law. Besides it dosent say that the temperature lingers it could cool instantly to regular temperature then when you cast it again you'd be back at square one, the spells wouldnt be overlapping they'd be instantly after one another.

oh yeah its taking serious liberties with the spell, but i was just trying to clarify what his original idea was, which i think would probably work. although i know nothing about thermodynamics so..

EDIT: or if this has anything to do with thermodynamics....

also at ninja_prawn and dire sturge:

minor burn? changing the temperature of somebodies body by 50 degrees will straight up kill them guys...hell changing the temperature of the human body just 10 degrees (FAHRENHEIT not even Celsius) would result in death.

the human body is a fragile thing, and now we know prestidigitation is an instakill assassination technique....nvm non living thing only. well played WotC

[SharkForce]

if you break the lock in the locked position, it isn't going to do you much good.

but if you really wanna break stuff, bring along a water skin and the shape water cantrip. fill object with water. use shape water to turn the water to ice.

[PoeticDwarf]

With prestidigitation you can chill or warm an inanimate object of size blah blah blah..

lets say i hold a spoon. And cast Prestidigitation to chill it or warm it..
i assume that it doesn't have a large range of temperature change.. lets say 5C for lower and 45C for higher? (a metal bar under the summer sun can easilly reach 65-90 degrees)

My question is.. this temperature change happens at once or it slowly starts to change temperature ??

The spell says instantaneous so i tend to choose the former.

The thing is..
The is a door with a lock on it. I touch the lock, and cast Prestidigitation to change its temperature fast from 10 to 50C.
after like 10-20 castings the lock will break of fatique... or at best will loose so much integrity that with a hard knock will break.

Is this a thing ??
I mean.. it is not RAI.. but.. it can happen if your DM is in physics.. shouldn't it?

It happens at once, I don't see how it NOT happens at once.

[Arial Black]

Spells do exactly what they say they do, without reference to real-world physics.

Prestidigitation can change temperature several times, and at the end of the process will be at the most recent temperature. There will be absolutely no weakening or shattering, because the spell changes temperature, it doesn't weaken and it doesn't shatter.

[Gurka]

Nitpick: the OP never claimed to be melting the lock. They want to weaken it through rapid heating and cooling, which introduces thermal fatigue, enabling you to break the metal manually.

And I believe most locks, even in medieval settings, would be brass (or at least some manner of copper-alloy) rather than iron. Not that it really matters.

There's a variety of reasons it might not work, and a further variety of reasons it should not be allowed to work, however...

The way most antique locks were designed, they are what's called "fail secure", rather than "fail safe". Not that they named or even thought of it in such terms back then (that's modern nomenclature). Fail safe means that when the lock fails mechanically it leaves the door or object unsecured and open. Fail secure means that when the lock fails, it leaves the door or object secure and unable to be opened conventionally with even the proper key.

In other words, if you break most warded or bit and barrel locks (which are what existed way back then), all you do is keep yourself from retracting the bolt or latch, which is what actually holds the door secure. The lock is just a mechanism to engage and disengage it. Even modern day locks are far more likely to get stuck in the locked position when they fail mechanically.

[-Jynx-]

What if you use prestidigitation to say heat the lock 10-15 degrees. Then use shape water to force water into the lock and freeze it instantly.

On that note... If you used shape water to make a key and froze it... How strong is ice in comparison to a lock?

[GiantOctopodes]

First, from a mechanical standpoint:
As a cantrip which specifically states it causes harmless sensory illusions and provides examples of non-damaging effects it cause, there is nothing in the description of the spell to support it dealing damage, to a creature or object, through any means. As such, dealing structural damage to an object's HP is outside the bounds of the spell.

Secondly, from a physics standpoint:
Most objects in D&D are created using construction methods that are significantly cruder, and significantly stronger, than modern methods. There is no standardized part sizes (except maybe in Gnomish engineering), it's all hand crafted by blacksmiths using what we would consider an absurdly large amount of metal to do so. The fit of components, being less precise, would also thus be less susceptible to thermal fatigue. After all, if there is sufficient room to allow the natural expansion and contraction of the material in play at that temperature range, the effects of temperature variance is greatly diminished. So, unless you are using Ray of Frost and Fire Bolt over and over (which I would absolutely allow to work, but the door would likely be destroyed before the lock, just saying) it is unlikely you'll get enough temperature variance to have a significant effect.

Third, from a fun standpoint:
Allowing this would completely negate the usefulness of Knock (very much so, since this in theory would be silent), allowing a Cantrip to wipe out a 2nd level spell. It would also diminish the usefulness of Rogues and anyone else who had spent effort and character choices in the bypassing of locks. Honestly, too, it's just not very heroic or cool (imho), sitting there fiddling with this thing for several minutes.

So overall, NO.
Would I allow Presdigitation's heating or cooling to provide other mechanical benefits related to expansion or contraction of materials for clever players, such as heating up a pair of manacles to make them looser and more easily escaped from, providing advantage on the relevant check to escape? Sure! Heating up paper or hemp objects to make them more likely to catch on fire, cooling objects to make them less likely to catch on fire, having a heated pair of manacles placed on a creature then cooling them to cause them to contract, making it more difficult for them to escape, there are many places where I would allow a mechanical benefit to be gained from the use of this aspect of presdigitation. Just not in the fashion described.


Edit:

What if you use prestidigitation to say heat the lock 10-15 degrees. Then use shape water to force water into the lock and freeze it instantly.

On that note... If you used shape water to make a key and froze it... How strong is ice in comparison to a lock?

Not very.

Ice expands outward from where the water is. Due to the way locks work, what this would actually do is just jam the lock, preventing it from being turned. A great way to prevent a lock from being picked behind you, not very good for opening them.
Think of it this way- there are tumblers, and when they are all at the proper height, the lock can be turned, releasing the deadbolt or other locking mechanism. The chance of the ice putting the tumblers at the right height is basically 0. In addition, now being frozen, even if they were at the right height, they could not be turned, and thus could not release the locking mechanism. And since only the key area, with the tumblers, is accessible, and not the locking mechanism itself, if anything were to be damaged, it would be the tumblers, preventing the door or object from being locked or unlocked, but not undoing in any way the locking mechanism.

[Ninja_Prawn]

hand crafted by blacksmiths using what we would consider an absurdly large amount of metal

*GOOlock invokes otherworldly power to cast Sending*

Modern Human: Eh, I've got an iPhone in my pocket and a Blackberry in my other pocket.

*MH looks at a lock*

MH: That's... that's ABSURD! I just... I just can't... *screams*

[Demonic Spoon]

various good reasons



4. From a roleplay standpoint: Your character probably does not have the required education in thermodynamics to even know why this idea would work, let alone come up with it.

[-Jynx-]

4. From a roleplay standpoint: Your character probably does not have the required education in thermodynamics to even know why this idea would work, let alone come up with it.

Just smart enough to understand magic and how it works, but just dumb enough to not know that quickly heating/cooling metal weakens it .

[Gurka]

Think of it this way- there are tumblers, and when they are all at the proper height, the lock can be turned, releasing the deadbolt or other locking mechanism. The chance of the ice putting the tumblers at the right height is basically 0. In addition, now being frozen, even if they were at the right height, they could not be turned, and thus could not release the locking mechanism. And since only the key area, with the tumblers, is accessible, and not the locking mechanism itself, if anything were to be damaged, it would be the tumblers, preventing the door or object from being locked or unlocked, but not undoing in any way the locking mechanism.

Though essentially correct, what you're describing are modern pin or wafer tumbler locks, which were not invented until the late 1800's. Not to say that they could not be in a fantasy setting, but warded locks and bit & barrel locks were more common prior to the industrial revolution. They utilize "skeleton" keys that we're all used to seeing on TV and in movies, and the older they get, the less key-like the keys look. They still essentially function the say way though, in that the key avoids the wards, pushes the levers aside, and allows the bolt or latch to be retracted. Damage either the wards or the levers, and the lock ceases to function, and you have to get it out the hard way.


4. From a roleplay standpoint: Your character probably does not have the required education in thermodynamics to even know why this idea would work, let alone come up with it.

Why not? A background in metal-crafting (such as being a blacksmith) would offer knowledge of how to temper metal, and what happens to even well tempered steel when it's rapidly headed and cooled again, thus losing it's temper and becoming brittle. They wouldn't use the nomenclature of "metal fatigue", but they still understood the concepts, so it's not out of bounds for a character to know that either.

[1Forge]

There's a variety of reasons it might not work, and a further variety of reasons it should not be allowed to work, however...

The way most antique locks were designed, they are what's called "fail secure", rather than "fail safe". Not that they named or even thought of it in such terms back then (that's modern nomenclature). Fail safe means that when the lock fails mechanically it leaves the door or object unsecured and open. Fail secure means that when the lock fails, it leaves the door or object secure and unable to be opened conventionally with even the proper key.

In other words, if you break most warded or bit and barrel locks (which are what existed way back then), all you do is keep yourself from retracting the bolt or latch, which is what actually holds the door secure. The lock is just a mechanism to engage and disengage it. Even modern day locks are far more likely to get stuck in the locked position when they fail mechanically.

I forgot about this, but this is true also considering most locks were dead-bolts.

[Vogonjeltz]

With prestidigitation you can chill or warm an inanimate object of size blah blah blah..

lets say i hold a spoon. And cast Prestidigitation to chill it or warm it..
i assume that it doesn't have a large range of temperature change.. lets say 5C for lower and 45C for higher? (a metal bar under the summer sun can easilly reach 65-90 degrees)

My question is.. this temperature change happens at once or it slowly starts to change temperature ??

The spell says instantaneous so i tend to choose the former.

The thing is..
The is a door with a lock on it. I touch the lock, and cast Prestidigitation to change its temperature fast from 10 to 50C.
after like 10-20 castings the lock will break of fatique... or at best will loose so much integrity that with a hard knock will break.

Is this a thing ??
I mean.. it is not RAI.. but.. it can happen if your DM is in physics.. shouldn't it?

First off, 50 celsius is not simply warm, it's definitely hot despite being below the boiling point.
Second, that being said, it's still not extreme enough to warrant metal fatigue.
We're talking temperatures extremes over the course of years to induce such failures. So 20 castings? No, more like 10^6 or 10^7 cycles and even then it would need substantially different ranges. We're talking below 0 degrees (which is not merely chill, but frozen) and more than half the melting point of the lock (assuming it's iron we're talking 1/2 of 1538 celsius, a tad above 50).


Nitpick: the OP never claimed to be melting the lock. They want to weaken it through rapid heating and cooling, which introduces thermal fatigue, enabling you to break the metal manually.

And I believe most locks, even in medieval settings, would be brass (or at least some manner of copper-alloy) rather than iron. Not that it really matters.

You are correct that it wouldn't matter if it were brass, the melting point of which is 900-940 celsius. Although it's a clever thought, trying to break a lock using metal fatigue, Prestidigitation is incapable of causing such a thing.

[Socko525]

Just take mending instead. Break the lock, get into the room and then mend the lock so there's no trace of you entering the room in the first place.