D&D General Physics of Sonic/Thunder Energy Type

[Cadence]

I don't know if it helps you or not, but here's how my brain unpacks them.

Force is the push or pull effect that one object produces on another object. It's measured in Newtons, and 1 N = 1kg ^. m/s². It's very needy...it needs mass, distance, and acceleration...if you're missing one of those, you don't have Force, you have...something else.

Energy is a measure of the work done when an object moves. It's measured in Joules, and 1 J = 1kg ^. m²/s^-2. See how you're squaring the meter in the units? That's because you're multiplying a force (in Newtons) by distance (in meters), thus squaring the meter. It's slightly more complicated than this, but work with me here.

TL;DR: Force makes Energy when it moves something.

That resonant frequency that people are talking about upthread is the rapid vibration of molecules (tiny mass, tiny distances, but they add up in a hurry)...when you get one end of an object to move in a different direction as its other end, and get it to move far enough, the object will break down.

Speaking of breaking down:

All of this falls apart in D&D because you can create work without using energy, and you can create energy without mass or displacement. That's the magic of...well, magic. It's why an arrow will never be the same as a firebolt, and why the world's most highly-skilled swordsman can never be as dangerous as a first-year Hogwarts student, and we will forever be arguing about Fighters vs. Wizards. We've seen crossbow bolts and swords, but nobody's ever seen magic. Physics goes out the window, and everything scales to infinity.

This image doesn't really help explain anything; I just thought it was worth a chuckle.

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I just need to get my brain to a handwavey enough state. I don't need to channel up the full Watts= kg m^2 /s^3. (And I'm going to try and fall to avoid thinking of what a Dragon with Relativistic or Quantum or Quantum Entanglement breath would be...)

 

[CleverNickName]

I just need to get my brain to a handwavey enough state. I don't need to channel up the full Watts= kg m^2 /s^3. (And I'm going to try and fall to avoid thinking of what a Dragon with Relativistic or Quantum or Quantum Entanglement breath would be...)

It's really the only way to do it, tbh.

I remember one time, one of my players just had to calculate the terminal velocity of his character in freefall. Something about falling damage would max out at 150d6? I don't know why he needed to know that, or what point he was trying to prove, because after he was done with his very dull physics lesson about it, I said "If you jump off of that 2000-foot cliff, you won't be rolling up the damage--you'll be rolling up a new character."

 

[Cadence]

It's really the only way to do it, tbh.

I remember one time, one of my players just had to calculate the terminal velocity of his character in freefall. Something about falling damage would max out at 150d6? I don't know why he needed to know that, or what point he was trying to prove, because after he was done with his very dull physics lesson about it, I said "If you jump off of that 2000-foot cliff, you won't be rolling up the damage--you'll be rolling up a new character."

My problem has just been trying to figure out what effect to give it in game that would be different than force that made sense. Resonant frequency damage is one. But then I just need to give it enough faux science cover to not hate it. So maybe a discrete set of levels of resonant frequencies (are stone and bone the same or different) and things that don't have one (oozes? some metals?). Or maybe it's all just the same?

 

[CleverNickName]

My problem has just been trying to figure out what effect to give it in game that would be different than force that made sense. Resonant frequency damage is one. But then I just need to give it enough faux science cover to not hate it. So maybe a discrete set of levels of resonant frequencies (are stone and bone the same or different) and things that don't have one (oozes? some metals?). Or maybe it's all just the same?

Oof, you might want to save yourself the pain and make all of them the same.

The Shatter spell might be a good place to start, now that I think about it. It does Thunder damage, and it's described as a "sudden loud ringing noise, painfully intense." Targets are allowed a Constitution save for half damage, and "a creature made of inorganic material such as stone, crystal, or metal has disadvantage on this saving throw."

It would seem that, for this one spell at least, Thunder damage is being used to describe harmonic vibration.

 

[Cadence]

Oof, you might want to save yourself the pain and make all of them the same.

The Shatter spell might be a good place to start, now that I think about it. It does Thunder damage, and it's described as a "sudden loud ringing noise, painfully intense." Targets are allowed a Constitution save for half damage, and "a creature made of inorganic material such as stone, crystal, or metal has disadvantage on this saving throw."

It would seem that, for this one spell at least, Thunder damage is being used to describe harmonic vibration.

Apparently I'm trying to avoid doing any IRL work I might have on my list tonight.

Would you give something with no hard parts (oozes, slimes, etc ...) advantage on the save?

 

[aco175]

5e doesn't have sonic damage anymore, everything is thunder now.

 

[CleverNickName]

Apparently I'm trying to avoid doing any IRL work I might have on my list tonight.

Would you give something with no hard parts (oozes, slimes, etc ...) advantage on the save?

Sure, why not? "Incorporeal creatures, Elementals, and Oozes make this save throw at Advantage."

Though I'd probably say that incorporeal creatures are immune/unaffected, since they don't have any molecules to vibrate...

 

[jgsugden]

Seriously: Damage from Magic in D&D should not try to follow real world physics. A fireball makes no sense. Why does it burn, but have no concussive blast? Why is it as intense 20 feet out as at the epicenter - but non-existant at 21 feet out?

The way I've approach it for 40 years: Magic was shaped to look like phenomena people may have experienced through real world examples. A Cone of Cold may be designed to make things cold and leave them looking like they fell in a lake and froze to death. But, that doesn't mean that what happens is exactly like falling in a lake and freezing to death. A fireball may look like an explosion, but that doesn't mean there is an explosion at the heart of that flash of fire energy. The magic simulates things that can happen in real life, but does so poorly.

To that end, a Thunderwave 5E spell is a blast of thunder damage that makes noise that can be heard well nearby, but not at all at a medium range - and it accompanies the blast of thunder damage with a repelling force that moves objects and creatures. How it does it is: Magic. How it works is: Magic. What it is meant to look like is a loud concussive blast - but it does a @#$# poor immitation of it.

 

[Cadence]

5e doesn't have sonic damage anymore, everything is thunder now.

Being "Thunder" almost feels worse (oooh, it rattled the windows)

Seriously: Damage from Magic in D&D should not try to follow real world physics. A fireball makes no sense. Why does it burn, but have no concussive blast? Why is it as intense 20 feet out as at the epicenter - but non-existant at 21 feet out?

I mean, even worse in the new ones it doesn't catch paper you're holding on fire (for those following the RAW).

The way I've approach it for 40 years: Magic was shaped to look like phenomena people may have experienced through real world examples. A Cone of Cold may be designed to make things cold and leave them looking like they fell in a lake and froze to death. But, that doesn't mean that what happens is exactly like falling in a lake and freezing to death. A fireball may look like an explosion, but that doesn't mean there is an explosion at the heart of that flash of fire energy. The magic simulates things that can happen in real life, but does so poorly.

To that end, a Thunderwave 5E spell is a blast of thunder damage that makes noise that can be heard well nearby, but not at all at a medium range - and it accompanies the blast of thunder damage with a repelling force that moves objects and creatures. How it does it is: Magic. How it works is: Magic. What it is meant to look like is a loud concussive blast - but it does a @#$# poor immitation of it.

I'm good with it being magic... I just need to have something in my head about what it is.

What makes a concussive blast different than force? Why is the effect of Shatter that is also thunder totally different?

 

[Oofta]

When it comes to magic, we can't compare it to real world effects. For example a fireball is not caused by a rapid chemical reaction, fire is just spontaneously created in the entire area. There might be some heat if you're outside the area, but you don't get burned. It likely doesn't even consume any oxygen.

It's the same with the other types. Thunder is everything in the area vibrating, including air. With thunderwave the vibration emanates from the caster, the air in front of them is compressed causing concussion force. Shatter vibrates everything in the area, including creatures, objects and of course the air.That air getting vibrated which is heard as sound.

Force is a bit different, in cases like magic missile it's like a Star atrek phaser, it's energy that disrupts living tissue. Wall of Force is, of course a force field, instead of disrupting its not allowing any change.

Anyway, that's always been my head canon.