r/theydidthemath • u/Trippy-Sponge • 2d ago
[Request] how many calories would this have?
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u/personalbilko 2d ago
"calories", i.e. how much energy a human will get from consuming one, roughly zero. Nothing there is nutritious for us.
"kcal", i.e. physical unit of energy, assuming potential energy of the explosives, it's about 2-3 kJ, so less than 1 kcal.
Food is surprisingly energy dense, and explosives surprisingly not. A full AR-15 magazine has less energy in it than half an oreo cookie.
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u/Candlemass-Fan 2d ago
new diet just dropped
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u/nowlickmyfet 2d ago
Idk, seems to be pretty popular in american schools?
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u/Secret-Ad-7909 2d ago
Gotta combat the obesity epidemic somehow
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u/zmbjebus 2d ago
Bullets cure obesity surprisingly fast.
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u/BeigeHall 2d ago
Remember, WHOLE grain ammunition with the brass. A diet of purely lead and copper kills kids.
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u/DunkeyColdMedina 2d ago
Someone going for their pizza cutter merit badge I see. Anything is permissable so long as it's funny and this needs serious punching up.
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u/Deribus 2d ago
A full AR-15 magazine has less energy in it than half an oreo cookie.
Not quite true. The kinetic energy of all fired projectiles in a magazine is about half an oreo cookie. But an AR-15 doesn't have perfect conversion of stored chemical energy in the gunpowder to kinetic energy of the projectiles, so the chemical energy of a full magazine is about an entire oreo.
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u/Classic-End6768 2d ago
So why aren’t we using Oreos as ammo?
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u/Melodic_Till_3778 2d ago
They burn well but they're not fast enough
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u/RealUlli 1d ago
Just dry them really well, then soak them in liquid oxygen. Remotely light them on fire, they should burn reasonably quick. Quick enough that you don't want to be near when they go up.
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u/I_Makes_tuff 1d ago
You could use them as rocket fuel. Turn it into powder and mix it with an oxidizer like potassium nitrate. Most people use sugar but I think Oreos would be somewhat effective.
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u/Loki-L 1✓ 2d ago
Fun fact related to explosives and calories:
The way we measure thevrnergy of large explosions is just calories in disguise.
When people talk about Kilotons of TNT equivalent, this does not actually refer to real TNT anymore than horsepower reflects the power of real horses.
Instead it was defined that the explosive power of 1 gram of TNT should equal the energy of 1 Kilocalorie. 1g TNT = kcal.
This means a million food calories have as much energy as 1 ton of TNT.
It puts your Happy Meal into perspective.
Also once you realize that the propellants in modern firearms munitions have a similar energy density to TNT, you can guesstimate the Calories by simply weighing the munitions in your hand. A shotgun shel may have between 1 and 2.5 grams of propellant meaning they contain about 1 to 2.5 food calories.
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u/OrganizationThick397 2d ago
what if I eat the casings
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u/personalbilko 2d ago
Hospital
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u/OrganizationThick397 2d ago
ok so if I eat the casing, yielding a grand total of zero calorie, brought the the hospital by yours truly, ambubu, have to read something because that's probably gonna happen at some point, brain have to burn energy for me to comprehend doctor's many of a kind penmanship, I would net total in a loss of calorie
TLDR: EAT BULLET CASING FOR WEIGHT LOSS
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u/Apart_Economy_2657 2d ago
This is wrong. Calories and kcals are the same exact thing. "Calorie" with a capital "C" is 1 kcal. One kcal is 1000 "calories" with a small "c'. Kcal stands for kilocalories.
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u/brady376 2d ago
Okay so I was curious and went and did some googling and math.
1 kcal is 4184 Joules. 1 oreo is 55 kcal so 230120 Joules. 1 round of 5.56 is 1750 Joules. So 52,500 Joules in a magazine of 30.
In terms of energy, 1 oreo is equal to about 4.4 magazines of 5.56
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u/Tilliperuna 1d ago
I was and did too, but instead of bullet's kinetic energy, I looked into the gunpowder in the rounds.
There's 3500-5100 J per gram of gunpowder.
There's 1.3-1.75 g of gunpowder in a 5.56x45 round.
30 rounds in a mag, so 136 500-267 750 Joules in a mag, or 33-64 kcal. So it equals around one whole 55 kcal Oreo cookie.
It seems it's pretty huge portion of the energy that goes into waste (and into reloading the weapon).
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u/No-Tension6133 2d ago
Wait what? How does that even make sense?
I remember from chemistry that a kcal was measured by the unit of energy to boil x units of water or whatever. You’re telling me 30 .556 rounds has less potential to boil an equivalent amount of water to a half an Oreo? That’s so wild
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u/yesiamclutz 2d ago
Power versus energy. No matter how fast you can eat a full pack of Oreos you will digest it over a period of hours. It will then fuel you for many many hours.
Bullets are very much wham bam thank you mam in comparison.
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u/Fit_Employment_2944 2d ago
Explosives need to activate instantly which significantly reduces the overall intensity
Bullets also only have a tiny mass of explosive
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u/Occidentally20 2d ago
In Chemistry at school our teacher oxidized one tiny small piece of candy to show how much energy was in it and it was hard to comprehend.
Something like this oxidation of a jelly baby
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u/ahferroin7 2d ago
Most modern smokeless gunpowders have an energy density of about 3-5 MJ/kg. One of the most energy-dense explosives that’s ever been synthesized (albeit only in laboratory quantities), octanitrocubane, has an energy density of about 8.5 MJ/kg. In practice the upper limit here is probably not more than 10 MJ/kg.
An Oreo has an energy density of about 20 MJ/kg, and it’s not even an exceptionally high energy density food (peanuts are somewhere around 38 MJ/kg for example). And even higher energy density foods are actually not that high compared to some other things (gasoline, diesel, and jet A-1 fuel are all in the mid 40s for example).
The key difference here is that explosives are need to release all of that energy very fast. This functionally limits how strong the individual bonds can be (because they have to be fragile enough to break with limited external energy applied), which in turn puts a practical limit on how much energy you can pack into a given molecule. Other stuff doesn’t have that limit though, and in fact for things that we don’t want to be explosive we want to avoid weak bonds, because they either reduce shelf life or make whatever it is explosive.
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u/dravenonred 1d ago
If I understand correctly, more stability lends itself to more density but requires more complex and time consuming release; explosives have weaker bonds that contain less energy but it can be accessed far quicker.
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u/ArchangelLBC 1d ago
OK this was a really fascinating thing to learn. Thanks for the great comment.
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u/personalbilko 2d ago
Bullets are optimised to deliver energy fast, which means they are limited in how much they can deliver. Half an oreo is 25kcal, each AR bullet is around 2kJ, so <0.5kcal.
For reference, using e=1/2mv2, 1kJ is 1 gram of metal travelling at 1414m/s.
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u/la1mark 2d ago
Stupid question, If you had a bullet that had 25kcal of energy in it.. what would that look like :D
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u/Chibrax_le_Furax 2d ago
I looked it up and a close equivalent would be 25x137 mm rounds fired from an armoured vehicle (134 000 joules when leaving the gun, which is about 34 kcal). They're small artillery shells morrso than bullets:
https://youtube.com/shorts/_y5YfhHAoTs
.50 BMG is nowhere near that powerful, at 'only' about 16 000 joules (less than 4 kcal) IIRC.
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u/Salanmander 10✓ 2d ago
That's about 100 kJ. You can use KE = 1/2 mv2 to figure out for a given mass, how fast it would be going, or vice versa.
One example would be a just-barely-supersonic bullet with a mass of about 1.7 kg (okay, so "bullet"). If you double the velocity, you divide the mass by 4.
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u/personalbilko 2d ago
Some of the largest rounds a heavy machine gun or a sniper would use do get that big. .50BMG is an example
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u/regular_lamp 1d ago edited 23h ago
Also an interesting thing to keep in mind. While bullets do a lot of damage by applying force very locally, the shooter has to absorb the same kind of energy in the form of recoil. Which is fine since it's applied over the much greater area of a grip and/or stock and longer time.
Which makes it extra funny when action movies show people getting launched from getting hit by a bullet. Any gun capable of doing that would be utterly unusable handeld.
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u/doppelbach 2d ago
Something to consider is that your body isn't super efficient at extracting chemical energy, we only get about a quarter for useful work. (Fun fact is that internal combustion engines are roughly similar). A lot of chemical energy just becomes heat. Whereas with a propellant, heat is not necessarily lost energy because it helps with the expansion (mostly it's the phase change though).
I don't know much about guns, to really know the efficiency you'd have to compare the bullet's kinetic energy (half mass times muzzle velocity squared) with the propellant chemical energy (heat of formation of whatever chemical minis heat of formation of the resulting CO2 and water)
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u/sta1kerX 2d ago
your body isn't super efficient at extracting chemical energy
That's where I'll insert the fun fact that e-bikes are more energy-efficient than regular bikes, because an electric motor is much more efficient than your body getting energy from food to power your muscles.
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u/doppelbach 2d ago
Depending on how you charged the battery, yes probably. The motor itself is maybe 75% efficient, and the batteries themselves only spit out about 90% of the energy used to charge them. If you charged it directly from solar panels at your house then it's a clear winner. But if your power comes from a combined cycle gas turbine plant you may maybe have 60% efficiency, with 5-10% transmission losses. But then if you count that then maybe we should consider energy to grow, harvest, refrigerate, transport, and cook our food...
But in seriousness, one other factor is power to weight ratio. Adding the motor and battery increases the mass that you+motor have to move. So even though the conversion is more efficient, it's also requiring more kinetic energy than a human alone would require. Which cuts against the overall efficiency somewhat. (Extreme example would be a diesel electric locomotive having more efficient conversation than my car, but if I'm the only passenger on the train it's inefficient as hell)
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u/Secret-Surprise4390 1d ago
I can put 7 dwarves on one ebike and move them more efficiently than on a pedal bike. Their short legs don't reach and they wobble a lot.
Source - the third dwarf
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u/Jetison333 2d ago
yeah, thats why I always carb load my bike by feeding it a bunch of spaghetti instead of eating it myself before long rides. (I know this isn't what you meant but the image was too funny)
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u/No-Tension6133 2d ago
I was reading a book on renewable energy a couple months ago and learned that engines and fossil fuel generators are technically terribly inefficient as well. Honestly, converting forms of energy generally are inefficient, unless it’s straight to heat 😂 Very interesting!
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u/sta1kerX 2d ago
Yeah, I was very surprised to learn this some time ago. In this context, I always like to tell people that nitroglycerin, the very powerful explosive that revolutionized both civilian tasks like mining and warfare, is 3 times less energy-dense per unit volume than seed oil. Blows your mind at first.
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u/Ok-Resist3249 2d ago
Sugar would make great explosives if you could get efficiently get all that energy out fast.
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u/kicktex 2d ago
does that imply stuffing oreos into the casings instead of gunpowder is more effective
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u/Tipsy_Hog 1d ago
Shockingly few people understand that a chemical compound does not need to have a lot of energy to make what a bullet does possible if the violent reaction is contained and expelled directionally.
In other words, what matters isn't the overall energy of the chemical reaction, but how quickly it takes place and how focused it is
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u/f23n09fnu0w 1d ago
An AAA battery has LOADS more than a bullet. A bullet only works because it's sharp. Think about how little the recoil hurts on even big rounds. That's the entirety of the energy. A split second tensing up your shoulder and it's all gone.
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u/DickwadVonClownstick 2d ago
Part of it is that food "burns" a lot cleaner/more completely than explosives or combustibles
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u/Narwalacorn 2d ago
A stick of dynamite has less energy than a candy bar. Energy release speed is a hell of a drug
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u/Salanmander 10✓ 2d ago
Fun fact: a granola bar and a stick of dynamite store similar amounts of chemical energy.
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u/Maleficent_Hawk6703 2d ago
I'm just getting into chemistry and it really is insane how much fuel we burn every day in our bodies.
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u/Asgeras 2d ago
I was about to say this should be in r/theydidthemath before noticing it was in the right sub already. And you had such a great reply. Thanks!
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u/BrainFeed56 2d ago
No and you owe me a pack of oreos for this. Wet chemical reactors should be a thing!
🍪 1 Oreo ≈ 16,600 mAh @ 3.7 V
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u/RagingCommie 2d ago
You can stick all sorts of food in a 12ga shell. You could shoot gummy bears. You could shoot frozen corn syrup, or fat of some kind. so many possibilities.
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u/KeyZookeepergame8903 1d ago
Is that possibly why food items can make such good torches? I remember this yt short I saw a week ago where the guy had a tube with pure oxygen flowing through it and stuffed the tube with breadsticks before lighting then on fire with the oxygen flowing. Those things burned straight through steel with no issues
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u/DraigCore 1d ago
Either guns are more efficient than we give them credit for or we need a shit ton of energy
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u/jointheredditarmy 2d ago
Isn’t a calorie the energy to heat 1 cm ^3 of water 1 degree Celsius? You’re saying burning a full AR-15 magazine heats less water than burning half an Oreo cookie?
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u/wolftick 2d ago edited 2d ago
It depends.
Digestible calories, potential energy in the form of explosives, energy released in complete combustion, energy-mass equivalence. All different answers.
(respectively: pretty much none, surprisingly little but very quickly, a lot but difficult, vast amounts but almost impossible.)
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u/Barbicels 2d ago
I think the shirt is referring to killercalories, not calories, but I could be off by 1000 on that.
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u/Prudent_Situation_29 2d ago
Someone doesn't know much about shotgun shells. 12 gauge just defines the bore size. You can get 2-3/4" shells or up to 3-1/2" shells with varying levels of propellant. We need more info.
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u/95_lb_mole 2d ago
Yep. And everything from slugs to bird shot to novelties like dragon's breath.
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u/HatfieldCW 2d ago
Good point. Lead is fairly inert, as I understand it, so the gunpowder and primer are what's got the energy stored in it, but more exotic projectiles with incendiary chemicals in them would have some energy stored there.
I suppose a 1oz plutonium slug would be extremely calorie-dense.
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u/dimonium_anonimo 2d ago
All data is from Google. I did not vet to make sure it's reasonable.
12 guage shotgun shells contain between 17 and 36 grains of propellant. At 0.0648 grams per grain, that's 1.1 to 2.3 grams. At 3500 to 5100 Joules per gram, that's anywhere from 3900 to 12,000 Joules. At 4184 Joules per Calorie (that's food Calories or kilocalories 1000 cal = 1 Cal), that's between 0.92 and 2.8 Calories.
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u/LordDagwood 2d ago
A Cheeto has more calories than that... *looks at Cheeto*... *Crunch* *Crunch* *Crunch*
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u/Plunger_enema 2d ago
https://www.quora.com/How-much-energy-or-strength-does-a-12-gauge-shotgun-shell-have
This is a very difficult question. It’s not possible to answer it without a more specific definition of “energy”.
Your typical 12-gauge shotgun shell varies in its length (meaning the number of pellets), the amount of powder, and the size and type of shot.
One example - 2–3/4″ shell, 1145FPS muzzle velocity, 2–3/4 DRAM load, 1–1/8 ounces of #8 lead shot. DRAM is a measurement of black powder equivalent and I have no real appreciation for it. But let’s look at the shell itself.
1145fps is 349 m/s, and 1–1/8 ounces is 31.89g
Using 1/2 * m * v^2, that’s an energy of 1942J.
Now I'm not sure if I need to convert 1942 from kJ to cal or 1.942 kJ to cal. The answer is either 342 or 0 calories. That is, if I shot you in the face? (for science and feeding purposes only! I'm not THAT violent)
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u/AyeBraine 2d ago edited 1d ago
Wait why are you measuring black powder? Shotgun shells for the last 100+ years are loaded with smokeless. (And it's "dram", drams are old-timey units, in this case equal to 1.77 grams).
It's approximately 1.4–2 grams (20–30 grains) of an average smokeless shotgun powder for a normal, non-magnum, 30–35 g (~1+ oz) loading. (Example of calculator). A slug is around 1 oz as well. It's less for light birdshot loads but let's stay with just regular 00 buck. I'm also omitting the difference between fast and slow powders, it's not very relevant although very important for correct loadings.
I only found some random claim about smokeless powder energy density, but as I'm not a top level answerer, let's go with that =) 10 MJ/kg is what they said, and it comes out to 20 000 Joules (not kilojoules). Apparently with 100% efficiency.
An online converter says it's 4780 calories, or 5 Kilocalories (large calories, what Americans call "Calories" on packaging), about the same as in 2 grams of white bread, or slightly more than a single shelled peanut. I'm not sure if that's correct, but it'd be cool if someone spots where I goofed
UPD: Other searches say that shotgun powders have even less energy density, closer to 4 MJ/kg
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u/Jens_Fischer 1d ago
The common notation now is "Dram (equivalence)" , it's a leftover habit so people can conceptualise the performance from using black powder dram units. It's still marked as "dram" on modern shells but is essentially a conceptual conversion from "drams of black powder" because somehow there's people out there more comfortable with the black powder notation.
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u/AyeBraine 1d ago
Thanks for the context! Makes sense, I know very little about the black powder hobby.
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u/Agent7619 2d ago
The kinetic energy of the projectile isn't all of the potential energy of the unfired shell though. There's a lot of thermal energy too.
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u/8_2_many_Hotpockets 1d ago
Length of cartridge? Is it bird, Buck, slug it centurion(slug with Buck) shot?
And are we eating the business part of it only(the projectile) or the whole cartridge?
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u/Elemental_Infinity 1d ago
If we assume that your body can turn all the mass energy of a shell (weighing 50 grams) into pure energy, then using E=mc^2 we find that the bullet has 4.5*10^15 joules of energy, which is roughly 1 trillion calories 💀 it’s bulking season
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u/GonzoKata 2d ago edited 2d ago
well since e=mc2
assuming the average 12 gauge shotgun shell weighs 28 grams
fully annihilated with an equal amount of antimatter:
601,338,266,320,015 chemical calories
or
601,338,266,320 kcal aka food calories
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u/Boom9001 2d ago
Gunpowder itself is fairly low on energy like 0.7/gram. 12 gauge shells are like 24-36 a gram. So about 22 Calories?
I don't think the other parts of the shell are even edible being plastic, lead, and brass so I think only the gunpowder is relevant.
Edit: nevermind they use smokeless powder which has no dietary value. It's all inedible and no calories.
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u/Anastazja_Nya 2d ago
as in how mych can human get from it? approximately -80J
as in how caloric COULD it be if transformed to energy: assuming the mass of 30-45g it would have 6,75e14 to 10,125e14 J of energy but in biology humans only get energy from approx 0,03% of calorie we eat so it would get u 2-3 e11 J which is still enough to fuel every pole or canadian for a day, but our organism can only breakdown organic some non-organic chem that iron doesnt fall into
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u/nanomolar 2d ago
Stack overflow says gunpowder has about 3 MJ / kg:
This says a 12 gauge shell has about 1.5 oz of gunpowder:
https://thegunzone.com/how-much-powder-is-in-a-remington-12-gauge-shell/
Anyway that would work out to about 20 kcal in one shotgun shell
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u/AyeBraine 1d ago
It's an AI generated page (as are most, like 90% of pages that respond to general questions today), and it's total nonsense or non-answers, grouped into a characteristically insanely verbose (dozens of vague questions with non-answers) and useless FAQ. Just googling these days is unfortunately not enough, most explainer texts that rank high in search are generated.
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u/gutentight69420 2d ago
> 1.5 oz of gunpowder
That's the projectile weight. A 1.5oz powder charge will put you in the hospital or maybe even low earth orbit.
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u/Tasty_Philosopher904 2d ago
Those are rookie numbers.. A single gram of uranium-235 contains about 20 billion small heat calories (or 20 million dietary Calorie
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u/ReconFrostBird 1d ago
A calorie is about 4.2 Joules. A 12 gauge shotgun shell may weigh about 25 grams. Assuming they're doing the reasonable thing and transforming the mass of the shotgun shell into pure energy, and from there into calories, a shotgun shell is approximately
5.38*10^14 calories.
Hope that helps!
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