Boy does this ever bring me back to what was probably my first science class. My school book was entirely unsatisfying in telling me how this process could be done in my basement. I really like your high pressure window making method. I'll have to file that one away. Super interesting result also.
No practical, even vaguely related? I distinctly remember burning a small square of cracker on the end of a needle underneath a coke can half full of water, and measuring the temperature change to demonstrate roughly how calorimetry works.
There was an art project once, that actually got the process right: the exhibition had to be closed due to the smell. OH wait, you meant the calorimetric process… :-)
@Eddie Hitler I think half of us did peanuts and the other half did crackers, to measure the difference. If you claimed you had a peanut allergy I'm sure the teacher would have delighted in telling you to sit in the corner away from the experiment and watch the _other_ kids get to light things on fire.
@@mikebarnacle1469 as an example if you eat pure glucose (sugar) you probably won't have anything come out, that there's no water doesn't prevent it from being dissolved/absorbed.
@@satibel But where would it go? It has to leave the system somehow. Provided Ben's weight stayed the same. Sweat? Exhalation? How else can mass leave the body?
A week of Soylent *and* putting poop in his freeze dryer to make concentrated poop essence. Going the extra mile. I'm not sure I'd eat astronaut ice cream that came out of that machine any more though...
Really interesting video! I think it’s important to note though that 1g of soylent doesn’t go to 1g of poop. A lot of the mass is gonna be breathed out at co2. So even though the energy density of the poop may be almost as large as the food, that cannot be translated into an efficiency directly.
He's measuring how many calories are actually taken in by the body, not how many calories are expelled by the body through breathing or retained by the body in fat. If a 200 calorie item exits the body as 100 calories, that means you only need to burn 100 calories to work it off rather than 200 calories.
@@bkucenski that’s true, but the difficulty is identifying an “item”. A 200 calorie item can enter the body weighing 10 grams, then exit as a 100 calorie item weighing 5 grams (The missing mass is exhaled as CO2) If you simply took the energy density of the two and compared, you would think that no energy was consumed, as they are both 20 cal/g, even though 100 cal was consumed.
Really cool video! One theory I have why the efficiency is so low is if the digestive system is taking calories out of the food, it's also reducing it's mass. So in other words, the fecal matter is more concentrated than the input was. So for example, let's say you eat 100g and your body takes out 30%, the mass of the poop you'd have to burn would be 70g and not 100g. And in that case, with some foods that have a lot of flammable but not digestible calories, if the same mass is burned, I think it might be possible to have the poo contain more calories than the food, because it becomes more concentrated.
The "eua du toilet" bit had me laughing pretty hard. EDIT: damn it I wrote out a whole thing on how to improve this and it got deleted. One sec lemme re write EDIT 2 - electric poop-a-loo: Ok so some things that are important to keep in mine. First poop is about 30% bacteria, 30% fiber, 15-20% fats/protein/cell debris, and the rest insoluble minerals. The minerals explain the residue you saw. But the important thing is that poop is like a filter, its the concentrated waste resulting from lots of eating. Also the cell debris is important. Your body uses the calories and those get turned into biomass. But then the cells die and get yeeted out with the rest of it, so some of the input calories end up in the output as "spent" calories. So you need to calibrate the actual mass in vs mass out to account for all this. To do that there's some things you'd need to do. The easiest, though also the least pleasant would be to take a ton of laxatives to clear yourself totally out, then fast for 1 day. After that eat 1 days food, then fast again for another day That would suck, no question about it. But that way you know the only thing you collect would be the result of a single day of eating. A less painful way to do that would be to add some sort of insoluble non toxic fluorescent marker to the soylent and then when you eventually pass it, only collect the part of the sample that's glowing. Then weigh it and compare that to the mass of input soylent during that meal. Then perform the test on that sample. Should give a much cleaner result. Frankly this is way more playing with shit than I'd be comofrotable with but, would clean the data up a lot and resolve some of the myster
you would still not count all the carbon that was part of stuff that went in your mithocondria, you exhale that, around 270g/day. So the only way to keep track of that would be to use radioactive carbon in the soylent or something and collect all your exhalations
Been watching your channel for years and never commented. Just wanted to say thank you. The amount of time you spend on a 30min video must be insane. And its highly appreciated. Thank you.
15:05 Try a U shape groove (not too deep) for holding the silicon seal in place. Ideal is when the glass is pressed firmly down and barely touching the metal holder, that way the gap of exposed silicon seal to the burning environment is almost zero and the seal will last much longer. This technique is used in small (50a70cc) 2 stroke watercooled bike engines (pocketbike etc...)
Thank you for doing this! This has bugged me ever since we had to do calorimetry in high school science. I asked about the difference between flammable caloric content and what your body can use, and basically got told to shut up and burn my peanut so we could get on with it.
@@capekraken2672 not really true tbh, for basics absolutely, but academics exceed in killing passions. if there's anything your actually interested in, from my experience, its better to do it yourself. which sucks!
@@albertogregory9678 sure, but I would not go as far as stating it is a passion killer. Even if you absolutely know your passion (which is more rare than not for high schoolers), you need to know how to do other things than just your passion. As well, school (at least here in Australia), you can choose which subjects you do and which ones you want to excel at.
@@neil963 I find that extremely unlikely. Did you have home schooling? If not, you must have worked extremely hard to catch up. Even so, you still had schooling which was not my point
I TRUELY LOVE YOUR VIDEOS!!! Speaking as a person who uses a wheelchair and has a severe physical disability that keeps me from being able to use things like lathes and many other things I see you using all the time, your amazing videos keep me from going crazy thinking of all the things I wish I could do but cannot with my disability. The world really needs more people like you in it!!!
So you measured the flammable-calories per gram of each, but, if evaluating efficiency, wouldn't you have to also factor in how the amount that went in corresponds to the amount that went out?
That is a perfectly normal way to look at it. But knowing that factor presupposes that you know the efficiency number that is attempted to be derived. The alternate method is then comparing known mass and then seeing what energy remains in that mass. The end result is the same because if your gut is ~20% efficient (16K / 20K), then if you put in 0.5 grams, you'll get 0.4 grams out. That is equivalent to 20K Joules in 0.5 grams in and 16K Joules in 0.5 grams out.
The calories per gram is probably much less relevant than total grams input vs total grams output. You should be excreting a significant amount of mass as H2O and CO2, so for every 100 grams you consume, you likely only get half of that out in waste (totally made that fraction up. Anything between 30% and 80% seems plausible). Also, ion content (Na, K, some Mg and Ca as well) will be eliminated mostly through urine, and should be relatively low amounts in stool. Chemically, you would still expect stool to be largely the same as the food input in terms of carbon, hydrogen, nitrogen content, and comparable ratios of the assorted chemical bonds common to most organic compounds. Really not at all surprising that it's so close.
Would be interesting to find out the nature of the residue that was left after the burning in relation to total input-output, especially for 'artificial' food like this powdered stuff with nutrients added and subtracted.
Yeah, eating a gram of soylent almost certainly doesn't result in excreting a gram of poop. This is why food studies are very difficult - you have to completely control all intake and measure all output, which often requires more control over a human test subject than most ethical boards are willing to allow. The mineral deposits after the poop burning are an indication of this ratio - the tiny amount of minerals that weren't absorb were present in the poop, at levels higher than in the input. It might even be possible to use this mass change to work out the ratio of input to output, if you go through all of the inputs and work out which would become a gas and which would become a solid after burning... Probably not accurately, but good enough to get a rough estimate of the ratio.
To add another aspect to this, how can we be sure that the fecal matter is just what you ate, and not include a mix of dead cells/other parts the body no longer needs?
Fecal matter includes a lot of dead bacteria, undigested plant stuff, fat (2-15% of the solid part), 2-25% protein. Outside cells just flake off, and epithelial cells (insides of the stomach, intestines) also count as outside, so yes, they are also in the poop. Internal cells usually undergo aptoposis and macrophages (literally means large eater in Greek) "digest" the remains. (See also phagocytes, the cell-eaters, and efferocytosis, undertaking-of-cells or cell burial.) Basically neighbor cells recycle what they can, and empty the rest into the blood, then that finally gets to the urine.
@@iccuwarn1781 It's not just what you ate, for sure. Also, your body adds a ton of stuff, enzymes, acid, bile to neutralize the acid, and a constant layer of mucus to protect the inside of the digestive tract from eating itself away. I think dead cells are largely reabsorbed, except for bacteria that die in the intestine, and the skin that sloughs off the outside (and into the digestive tract, which is also kind of the outside, topologically speaking)
did i miss it somehow? where did you measure how much mass input results in how much output. there is a substantial amount exiting your body as co2 or pee. you'd need to monitor the output weight until it stabilizes over time to get a input to output factor btw. goofy face cover ftw please don't forget to clean the dryer before making new icream 🤣
That's a good point. If you take in 1kg of food with Xcal per g and poop out 100g of poop with also Xcal per g doesn't mean you didn't extract any energy at all. It means that you've extracted 90% of the energy. Input and output weight ratio is important
@@TimLF Good point, but I think that would be a very small amount. I mean, how many hairs/skin cells/whatever do you grow over a week? Not a lot probably
Here's a video idea: You can use your mass spectrometer and some isotopic water to measure exactly how many calories you've burned in up to about two weeks. It's called the "Doubly Labeled Water Test". The idea is that you drink some water with a safe percentage of both 18-O and 2-H in it (get by mixing partial 18-O water with partial deuterium water, each not terribly expensive) and 15 minutes later measure the baseline ratio of 18-O to 2-H in your urine. After however many days, the 18-O and 2-H will have diminished an equal amount by leaving the body as water, but only 18-O will have been incorporated into exhaled CO2, which by definition is a direct measure of calories burned. So at the end of that time period, the new ratio of 18-O to 2-H in your urine tells you exactly how many calories you've burned in that time. And all you need is the isotopic water and your mass spectrometer.
Very cool idea! But it just measures the energy you've burned during the time of measurement. Burning of fat already stored in the body as well as new deposits can not be monitored this way. I'd rather stay on his track measuring the source of energy instead of it's outcome as he tried. But he didn't account for the loss of mass since digesting means taking up the nutrients (and finally breathing them out as CO2). So i'd correct for this error by adding an undigestable stable compound not being absorbed by the body added to the soylent to correct this flaw.
you're my favorite youtube channel period. every single one of your projects is astoundingly high quality and fascinating. thank you for creating these videos for us, this is the reason the internet was created.
As may have been mentioned, a change in diet can quickly change the bacterial ratios in the gut. Carnivore diet proponents often report their first week of stools being very black and runny, and nutritionists have responded saying the bacteria responsible for digesting meat proteins are increasing in quantity while those for vegetable matter are significantly decreasing. This shedding of dead or dying gut bacteria from the intestinal lining could explain the higher caloric readings from your fecal sample. Fascinating experiment!! Man, I love this channel!!
Hi, a great experiment. I think that there is a more complex issue occurring here. Fecal matter consists of the residue of digestion but also contains the bacteria of the gut flora that are expelled, and the remains of the gut mucosa that is abraided as the bolus passes through the intestine. Additionally, there is the product that is secreted by the liver as a byproduct of blood cleansing and replacement. altogether "food for thought" Thanks for the fun, Richard
The fact that you went to these lengths for real world science has alone earned you my sub. Looking forward to working through your back catalogue. Sometimes the algorithm gets it right...
Not sure if I missed it somewhere, but aren't you comparing apples and oranges when comparing the energy density of the input and output matter like that, in that a certain amount of input might result in a much lower amount of output as the digestible bits are converted into water and CO2?
If he collects and dries all output, over long enough time to average out the fluctuations, he could establish the dry matter input:output ratio and get a more meaningful efficiency value.
He could used an inert non-digestible standard that could then be measured and used to determine the mass to burn in the calorimeter. No sure what or how (maybe mass spec) and I can be suer it would add significant cost/complexity
Your body also continuously disposes of dead cells, mostly dead blood cells which have a high calorific value. That brown color...iron. Awesome job on the experiment.
Yeah that is going to change the output if your body isn't working the same way 24/7... But I guess it wouldn't suddenly change by that much if the input is constant.. Except if you constipate for the duration of measurement, I guess.
The brown color is not iron, but instead bilirubin from breakdown of heme. Iron is far too precious in the human body to excrete willy-nilly: there are in fact no identified ways in which the human body can get rid of iron intentionally.
I gotta say that this is your best video yet. The fact that the entire journey is to test the human system is interesting, and having to learn about an entirely new device on the way there makes the whole thing amazing. Great video. Thanks for sharing your love of exploring with us. Trurhfully, since your passion is genuine, you could have just never uploaded anything way back at the channels beginning and remained perfectly satisfied. I'm really glad you did.
This was an awesome demo / experiment. I remember reading the details of calorimeters in university chemistry class, many years ago. We did the math, but I never understood any of the engineering behind how it would actually work. This was super cool to see done in real life! Thanks!
Exactly this. You exhale the "burned" carbon as C02 as you breathe, you don't defecate it out. Most of your fecal matter is bacterial colonization of the remnants that were not easily broken down into macronutrients and absorbed by the body.
I was just about to bring this up in a comment. It seems intuitive that it would take multiple grams of food to produce one gram of solid waste. Some of the mass difference ends up as metabolites in urine, some ends up exhaled as CO2. I'm just not sure what the ratio is.
@@MysticalDork Isn't that a point? If You exhale CO2 that means that it was digested and absorbed by human body. Everything "undigested" will end up as a waste.
@@Krawacik3d Still doesn't change the input-output ratio issue. If you eat 3lbs of food, but only excrete 8 ounces, even if they're the exact same energy density in the calorimeter, you're only leaving behind 1/6th the energy of the input in the output.
@@TrumpeterOnFire That's true. Now that I think about that measuring total amount of energy undigested should be easy knowing it's density and total weight, maybe Ben will make follow-up video regarding this.
Amazing engineering setup, but I think there is a little lack in microbiology plan. Poop is mainly consist of dead bacteria and some fibers. That bacteries were responsible in food digesting and the total process is too complicated to be resolved like as simple input/output example. But overall this is cool demonstration.
His experiment is a literal application of the first law of thermodynamics, his body being the control volume, and the efficiency calculation is applicable. Whatever energy was transformed by bacteria, it could not have been used by his body if it was still within the pooped bacteria.
@@homemdosaco2000 There are still considerations like the balance of bacterial biomass still in his body. It may fluctuate. More sampling over a long period of time along with body weight tracking might help trace possibly error. I also wonder if he used any stored fat during the experiment, or measurably lost any weight.
Agree that weight change can skew the calculation. Bacterial mass would come to an equilibrium with the controlled diet, but I have no idea how long that would take. However, I stand by my previous statement that whatever energy was pooped, did not contribute to his body functions.
@@homemdosaco2000 it's literally that simple, yet the comments insist different, demanding things that are empirically impossible to control for. The mystery has been solved. 'calories in calories out' is only 25% accurate
Hey Ben, I've had similar design challenges at work when working at high temperatures. Sizing the metal pipe ID for a close clearance fit and adding another step farther back where the plastic window begins and placing the O-ring there will prevent it from burning. Any hot gasses from the flame will cool flowing thru the narrow gap to below ignition temperatures before reaching the plastic and O-ring. Love your channel, keep up the good work!
Sir, you are a genius. I love your attention to detail, and I love your channel. Thank you for sharing your knowledge, your journeys, and your triumphs.
Hey Ben, interesting video as always. I do wonder, did you correct for total weight on the input and output side? If your body takes up a certain percentage of the input weight, only the remainder of that percentage is truly lost. If the total output weight is not the same as the input weight a comparison of joule per gram does not make sense right? Could that be the missing piece of information?
@@themadrobot he could measure the ash content of both materials to get a rough estimation, although you would probably need to purify the ash before measuring it to account for soluble substances like salts getting lost in other ways. This would be very complicated though.
Incredibly fascinating! I agree with a lot of the comments saying that the digest system is far more complicated than the simple input/outputs you used. But I didint know that when I watched this! Please keep up with these experiments. We may not get many solid conclusions but we will all certainly learn a lot more about human digestion.
W.r.t. the burst/leak thing at roughly 7:11, the determining factor of whether or not the plastic will also burst is if the speed of sound in the containing material is faster or slower than the speed of sound in your contained fluid. There was a silicon wafer plant somewhere that had a pipe full of silane explode every pipe in the plant because the speed of sound was faster in the pipe wall material, so the pressure relief wave in the silane was always slower than the pressure relief wave caused by the crack in the pipe. [edit]: related paper that I haven't had time to read yet: www.icheme.org/media/10230/xv-paper-15.pdf It looks like that it isn't the speed of sound in the pipe material, but rather the crack propagation speed, and there's some more complicated math going on than I initially thought. Still an interesting read.
@@rkan2 True, but that's a different failure mode. I'm referring to the pressure being specifically too much for the window. The seal burning through is the sort of problem that could've been solved with a correctly sized O-ring groove. 😉 Though it should be a fire-resistant material anyway given the environment.
That is a great Calorimetry setup! Your window making skills are legit. My first one involved a banana that I stabbed toothpicks into, placed foil on top of them, and a piece of popcorn under the foil...resting on the banana. Put some water on top the foil, burned the popcorn, then measured the change in temperature. Safe to say yours is a LITTLE bit better of a setup. Nice work!
Really cool video! Though I was under the impression that a large amount of the carbon we excrete is via respiration (2.3 lbs per day if I recall correctly). So factoring that in would probably be pretty important.
@@petros_adamopoulos What? Of course the carbon we exhale is usable. Not after being exhaled but before and it should definitely be accounted for in this balance.
@@petros_adamopoulos by definition, that carbon WAS useable carbon. The CO2 from your breath comes from the cellular respiration breaking down energetic molecules your body got from food.
As always, great video! The missing key in this experiment, as others have pointed out, is fuel weight compared to ash (fecal) weight. You really have to perform a chemical analysis of both the food as well as the fecal matter, sort of like a nutrition label for poop. Yeah... I think I won't go any further with that train of thought. I totally geeked out on your construction elements, starting with the composite window! Right as I thought to myself you should use a UV cure resin, I saw you waving the flashlight over the window. NICE! And I love your idea of cutting a gasket on a lathe with an Exacto blade! I may have to use that one! Thanks for the great video! Cheers!
This is a fascinating subject. I've always suspected calories from alcohol does not accurately portray digestible calories. It would be interesting to see an experiment with that premise. Thanks for the excellent content!
Oh thank god, someone who actually know something! I've thought about this very subject many times. I really appreciate seeing all the tips and trick of getting the experiment off the ground. Thanks for the video! By the way, for anyone working with high pressure oxygen, make sure you never allow hydrocarbons to come in contact with the oxygen and always use copper lines to transfer the O2. Stainless steel will become flammable at about 5 bar (75 psig ). Also, if you use PTFE tape, make sure it is certified for oxygen service. Oxygen certified PFTE has no oils that can burn. I have investigated several O2 explosion in the past few years where people have not headed these precautions. As to the calorific balance, how much input mass was there vs the output mass? E.G. If you ate 200 g of Soyulent and had 100g of fecal matter ...
Nice video man! You raising garage science to new heights. Please do the macro nutrients individual contributions to usable calories. Nutrition science is certainly one of the most contentious topics in physiology and medicine, going back to fundamentals like you habe is refreshingly straightforward...
Dear Sir Ben, This is Simon, a Engineering student at Rice. Thank you for the fun and detailed introduction about soylent and calorie test. I also like soy, besides spirulina, another plant-based food powder. Happy New Year.
This is what you call dedication to science, folks! Not going to lie, this question has crossed my mind as well but you actually went about answering it!
I’m a food scientist specialized in food chemistry. Let me know if you need any help with the determination if macronutrients! It would be great to contribute to your videos!
Soylent produces very consistent "results" :) I'm a food scientist too. Reading nutrition facts labels was one of the reasons that made me interested in the career. I really enjoyed the college class where we analyzed the nutrient composition of a food of our choice. I chose a Burger King Whopper :) It was so fun liquifying it in preparation for freeze drying, then having a taste of the whopper powder afterwards. It tasted great! (retained much of the flavor) Then extracting all the fat with hexane and nitrogen for protein. The lab manager ran the bomb calorimetry for us when we weren't around, so I never saw it in action. Finally, I now have!
This pipe bomb 😆 you made looks a lot like the regulators I build at work. We use 2024 aluminum, 7075 aluminum, cda 360 brass, Viton o-rings, Kel-F plastic and 303 stainless steel. And yes, Buna burns like a fuse in oxygen rich environments. Viton and silicon melt and burn, but buna/nitrile is almost explosive.
I was just amazed when you cut those gaskets on the lathe, that’s a brilliant idea. An idea for a flame proof gasket could be a copper ring or maybe flexible graphite
@Paul Skaar not sure about grafoil where there's fire and pure oxygen at high pressure. I'd expect some of that to be combusted. but maybe I'm wrong on that.
@@samalbury9183 i suspect it probably dosen't make a difference here with using copper gasket in vacuum vs hyperbaric. Does copper cold weld in vacuum conditions?
This is super interesting. I have always wondered about how little the human body can actually live on, and if it just changes input and output based on individual metabolism and nutrition conditions. One problem that I can see, and you probably have as well, is that I don't think you can compare grams for grams on input and output. Input could have ~5% fiber, where as your output could have ~25% fiber due to the body unable to process it and therefore concentrating the flammable calories in a smaller amount of waste. In this case you would need to get a ratio of the amount of food turns to actual solid waste, since the body has other processes that remove waste, breathing and urination. There is so much going on here. As always, so much information to process in your projects. Thanks for sharing.
This is awesome. Thank you for exploring this as it's an area I've always been super interested in. We hear diet is simply a matter of "calories in / calories out" as if humans are some 100% efficient bio machine able to absorb all forms of calories equally. It just doesn't make sense and no one can convince me that human bodies supposedly do the same thing with 100 calories of sugar vs 100 calories of protein. Food only stays in our system for so long and our ability to absorb and digest different food components has got to be variable which means depending on what you eat your efficiency is going to differ. There are probably tons of variables at play depending on the specific macros of the diet you consume. There're stories of people losing weight on a 2000 calorie McDonald's only diet and while it's true that person did lose weight on strictly counting calories I feel we totally miss the rest of the story and why. Could this individual have lost just as much weight eating 3600 calories of boneless skinless chicken breasts and broccoli? etc... super interesting, thanks for playing with your poop
I lost weight at 14kcal/day with moderate exercise generally just matching macros and completely ignoring how I got them, whether candy or fast food who cares. Growing up I've been generally in this a mode where I'm eating as little as possible, in which can totally maintain weight at 200-800/kcal a day. (As an average of 1 big meal every few weeks) But, if I eat regularly, such as any time I tried to get healthy, my body would just ramp up it's metabolism and be more hungry all the time, ramping up to generally 6kcal/day at sedentary assuming I'm just eating every day. The longer I power it, the more it starts burning, I swear, I can't maintain my body at full stroke like a reactor heating up. I'm generally always eating every few days to avoid getting too hungry and eating too much. Up until about 25 I never had more than 5% body fat despite....Hell, I could do 25kcal mcdonald diets and regularly ate 10kcal sedentary fast food with no impact, just living daily with an unhealthily low level of body fat. So this one time I was exercising. I was matching macros at the extreme bulking ratios and I was still losing weight, so I just decided to eat as much as I felt I needed to which ended up being 2-3x the extreme IIFYM calculator recommendations. When I finally started gaining weight, I was a 130lb kid eating literally 4-9lbs of food every day, half in fish and half in junkfood. Affter 2 months of eating 14-24kcal a day like that and my body capped out at 145lb... 15 extra pounds(0% fat, so not a bad job...just felt like wow, that much work to gain that little? Eh...not really worth the energy) and always eating and I just couldn't put any more weight after that. I got so tired of eating so much, spending 70% of my day working out and eating. I had to live singularly for my body if I actually wanted it to go anywhere, wouldn't even have time to stop chewing :/. So, I lost all the weight in 1/2 the time it took me to gain it and with 0 the effort. On the other side of it is that it's possible to fast for weeks with ounce losses when at equilibrium too, pretty wild. So, trying to push my weight up +10lbs takes an exponential amount of input so much so I cannot actively do it. And trying to lose 10lbs is pretty impossible too. Really makes you wonder what's going on e.e But yeah, I've eaten pounds of grease daily for months, with no appreciable effect except for the rumbling in your heart growing in intensity, like your blood's cholesterol is actually perceivable due to it's viscocity which causes high cholesterol blood to "rumble" more and thus you can feel the veins vibrate your skin more. I could be crazy, but every time I eat high satured fats and lots of junk food, It builds up, even you are more lethargic as if it's because it's harder to get nutrients around with fat kid blood...idk. Just years of anecdote. As a kid it built up way slower, as an adult I swear I have to be careful of grease. A few heavy days and I start noticing, vs teenage years and months without impact. Anyways a result of that sort of hypochondria, I have a pretty natural limit on eating just pure fats nowadays, I don't mind a meat stick here or there, but I'll start feeling like...my heart just working harder, the rumbling of your veins more, truly disgusting sensation...Gives me the willies e.e
@@GRAYgauss That was an interesting read. My brother is also afflicted with whatever genes are required to eat tons and stay lean. He hates it but I sure wish I had gotten those genes too. I'm the opposite. I have to fast and stay well below recommended calorie intake in order to maintain or simply not gain.
What is also going to offset these readings is that your body has a very long term storage. Combined with that it is constantly breaking down its own cells, primarily blood cells, results in fecal matter containing many elements that would not be in your nutrition from the past week.
Broken down body cells don't go into fecal matter, they are transported with lymphatic fluid and blood and end up in urine. However chemicals reused in digestive fluids such as spit and bile do get mixed into the digestive tract and may end up in fecal matter if not reabsorbed along usable food chemicals.
This is a great demonstration of calorimeter bomb. I've learned about the bomb in thermodynamic class, but never seen it work in real life. Thanks you !
Ugh, I hate to be *that person*, but the quote is actually credited to Adam Savage's ballistics consultant, Alex Jason. Adam overheard him say it after a tough shoot and stole it (with permission) to say on camera. :)
would be a better quote if science had actually been defined, but after 200 years of attempts I guess it's been agreed that it's not something distinct.
@@senselessnothing I think what defines science is that it makes falsifyable predictions and theories. And it is methodical. As long as you're writing down your observations you are potentially providing data for testing those predictions and theories.
@@kwinzman what you're describing is an old interpretation by popper and such, it's failed pretty miserably over the decades and was the last big interpretation out there.
ever since i learned that ICEs are about 20% effiecient in middle school ive always wondered whether i have a better fuel efficiency than my honda bike
On a pedal bike, you get about 1/38th miles per calorie. So if you ate gas, never slept, and never did anything else you could go 853 miles on a gallon. But you'd only be going about 15
This was fascinating! The best part of seeing the waste accumulation of mineral salts nodules and other non-digestible fibers expelled as compared to the input of viable nutrients. The human body being an efficient storage battery of nutrients until they are consumed as needed.
Too bad you couldn't find a thick quartz or borosilicate glass plug for the viewing window, but yours seems to work well. I love the method of making a silicone gasket. Always unique videos! A++
some materials can take a lot of sustained pressure, but i'd worry a sudden change (like underestimating how fast it would burn) might shock it into shattering regardless. his solution is probably safer overall.
the fact that glass has a statistical failure rate is really interesting so that means you can't trust it will break after 1000 uses, but instead that each use has a 1 in 1000 chance of failure?
Runforitman. This is generally correct. Architectural glass (e.g. window Glas) is typically closer to 7/1000. You can manipulate the ratio by “massaging” the material (e.g. grinding and polishing edges), but won’t change its inherent statistical nature.
This may already be in the comments below but here goes: YEARS ago in p-chem lab we just used (if I remember right) sodium nitrate in excess. For anyone trying this at home, this makes a much easier approach than using oxygen gas. Great video BTW.
2:45 Ben, you're really missing out on UA-cam clickbait potential ;) (though we're all glad you don't indulge in that stuff). Great video as always. 13:42 also made me laugh out loud XD
That clickbait thumbnail reminded me of one of his earlier vids about why he doesn't do clickbait thumbnails (and provides an example, similiar to this one) nice callback :D
@@dowdayjing8442 yes, they do. Maybe I should have explained a little: in clickbaity videos the title often includes a lot of !!!!!! However if you slip of the shift key while doing that you have !!!!1!! for example. It shows how sloppily it was done. But somehow accidentally getting a literal "one" in there would be tricky and quite funny :D
Question for thought, but isn’t the human waste condensed too? Its not 1 gram in = 1 gram out - what is the actual ratio of mass in to mass out? That also may shed some light on the efficiency numbers.
Results surprised me, and though me a lot. Somehow my brain was always just assuming that there is a "fire" in the stomach that would pull out >90% of the calories. This experiment is simply awesome and I will perhaps never look at the nutrition labels the same way again!
I like how you describe the process of success and failure. The whole time I was speaking aloud, what if you do this, what if you do that. Very fun and informative.
phosphates and sulfates seem pretty plausible. calcium sodium and potassium phosphates and sulfates wouldn't be gasses after burning, and have high melting points.
Thank you very much for the hard work you did to do this. It is impressive. And it shows how hard it is to get new science correct. Others have pointed out the flaws, so I’m not going to do that. I’ll guess that the body tends to be able to absorb 95% of the nutrients. Intestinal flora gets most of the remaining. If we weren’t getting nearly all the usable energy out of our food, evolution would have lengthened our small intestine. Here are some facts that I remember. Almond paste is fully absorbed, but almonds aren’t due to inadequate chewing. Feces includes fiber that was eaten, intestinal flora, and cell components-I have no idea the heat energy each has. Improvements to your methodology include measuring solid inputs and outputs, weighing urine and analyzing urine composition to calculate nitrogen loss, estimating respiration and calculating carbon loss, and estimating skin slough.
We use to make bio fuel out of poop and we realized we were getting massive amounts of iron slag developing on things during high temp burns, it was the iron in the blood that was in your waste. It was very surprising how much was in waste and how much slag would build up on things.
Great video, very interesting as always. I was so surprised to see such a basic mistake made though of comparing 'grams to grams' of soylent to dry poop. Obviously if you ate 1kg of soylent and pooped out 100g of poop, the poop could even have greater calorie density from the indigestible fibre, so it literally tells you nothing? Surely you'd have to clear out your system, eat a bunch of soylent, clear out your system again, and measure that. Even then, you'd have to take strong antibiotics to prevent the results being contaminated by biomass, and that would be awful for your health.
I have to say this: your face doesn't LOOK like that of a scientist, so your clear way of thinking, speech, research and presentation both surprises and amazes.
@@lucasg.5534 I may not have expressed myself clearly. What I meant is that if I met this guy on the street, I would have thought that he was just an "average Joe" without any advanced knowledge or skills, he just has that look/vibe. But when he starts elaborating and showing his research, it is clear that he is an intelligent and knowledgeable scientist, which simply doesn't match his appearance. Looks and first impressions can be very deceiving.
![Lp. Сердце Вселенной #60 РОЖДЕНИЕ ЛОЛОЛОШКИ [Финал] • Майнкрафт](http://i.ytimg.com/vi/YoR0pAV9FVQ/mqdefault.jpg)
Boy does this ever bring me back to what was probably my first science class. My school book was entirely unsatisfying in telling me how this process could be done in my basement. I really like your high pressure window making method. I'll have to file that one away.
Super interesting result also.
No practical, even vaguely related? I distinctly remember burning a small square of cracker on the end of a needle underneath a coke can half full of water, and measuring the temperature change to demonstrate roughly how calorimetry works.
There was an art project once, that actually got the process right: the exhibition had to be closed due to the smell.
OH wait, you meant the calorimetric process… :-)
@@PKMartin I might have done something of that kind. Hard to remember
@Eddie Hitler I think half of us did peanuts and the other half did crackers, to measure the difference. If you claimed you had a peanut allergy I'm sure the teacher would have delighted in telling you to sit in the corner away from the experiment and watch the _other_ kids get to light things on fire.
Love your channel, NightHawk
Thanks, this video convinced me. Finally going to replace my digestive tract with a flame
The test is flawed though since you could've transformed 1kg of Soylent into 50g of fecal matter and he's comparing the energy in 50g of each.
@@satibel that's a pretty big flaw
@@satibel How? It's dehydrated
@@mikebarnacle1469 as an example if you eat pure glucose (sugar) you probably won't have anything come out, that there's no water doesn't prevent it from being dissolved/absorbed.
@@satibel But where would it go? It has to leave the system somehow. Provided Ben's weight stayed the same. Sweat? Exhalation? How else can mass leave the body?
A week of Soylent... the sacrifices you make for science are beyond incredible.
A week of Soylent *and* putting poop in his freeze dryer to make concentrated poop essence. Going the extra mile. I'm not sure I'd eat astronaut ice cream that came out of that machine any more though...
What’s wrong with soylent? It nutritionally complete, fairly inexpensive and the cocoa flavour is great...sounds like fanboy fud
He's a bit redundant though... Soylent "Pre-digested" and Soylent "Post Digested," doesn't matter - it's all shit.
@@bryanl1984 coming in with the hot takes
@@epiccollision Is it the green Soylent that is made of rendered rabble?
Really interesting video! I think it’s important to note though that 1g of soylent doesn’t go to 1g of poop. A lot of the mass is gonna be breathed out at co2. So even though the energy density of the poop may be almost as large as the food, that cannot be translated into an efficiency directly.
Agree. The missing math is the ratio of dry powdered Soylent in the top end to dry powdered poop out the bottom end.
@@nedwelch1217 we just need to weigh the shit everytime we take one
He's measuring how many calories are actually taken in by the body, not how many calories are expelled by the body through breathing or retained by the body in fat.
If a 200 calorie item exits the body as 100 calories, that means you only need to burn 100 calories to work it off rather than 200 calories.
@@bkucenski that’s true, but the difficulty is identifying an “item”. A 200 calorie item can enter the body weighing 10 grams, then exit as a 100 calorie item weighing 5 grams (The missing mass is exhaled as CO2) If you simply took the energy density of the two and compared, you would think that no energy was consumed, as they are both 20 cal/g, even though 100 cal was consumed.
I came to the comment for this
Really cool video! One theory I have why the efficiency is so low is if the digestive system is taking calories out of the food, it's also reducing it's mass. So in other words, the fecal matter is more concentrated than the input was. So for example, let's say you eat 100g and your body takes out 30%, the mass of the poop you'd have to burn would be 70g and not 100g. And in that case, with some foods that have a lot of flammable but not digestible calories, if the same mass is burned, I think it might be possible to have the poo contain more calories than the food, because it becomes more concentrated.
He has parmesan goldfish crackers, not the standard, I like the idea that he's a goldfish cracker connoisseur
yeah it's funny to think of him being a snob when it comes to a toddler snack
@@Tr4cK17
Gross
💩
@@Tr4cK17 you could use it to cook your food, or heat up a small area use it as fertilizer.... I think that's why we have some burnables left over ;)
@@Tr4cK17 biomass reactors and other organisms take care of that, no need to eat your poop, lol
Ah yes ...but the Mickey Mouse ones are the most aesthetically pleasing.
The "eua du toilet" bit had me laughing pretty hard.
EDIT: damn it I wrote out a whole thing on how to improve this and it got deleted. One sec lemme re write
EDIT 2 - electric poop-a-loo:
Ok so some things that are important to keep in mine. First poop is about 30% bacteria, 30% fiber, 15-20% fats/protein/cell debris, and the rest insoluble minerals. The minerals explain the residue you saw. But the important thing is that poop is like a filter, its the concentrated waste resulting from lots of eating. Also the cell debris is important. Your body uses the calories and those get turned into biomass. But then the cells die and get yeeted out with the rest of it, so some of the input calories end up in the output as "spent" calories. So you need to calibrate the actual mass in vs mass out to account for all this.
To do that there's some things you'd need to do. The easiest, though also the least pleasant would be to take a ton of laxatives to clear yourself totally out, then fast for 1 day. After that eat 1 days food, then fast again for another day That would suck, no question about it. But that way you know the only thing you collect would be the result of a single day of eating. A less painful way to do that would be to add some sort of insoluble non toxic fluorescent marker to the soylent and then when you eventually pass it, only collect the part of the sample that's glowing. Then weigh it and compare that to the mass of input soylent during that meal. Then perform the test on that sample. Should give a much cleaner result.
Frankly this is way more playing with shit than I'd be comofrotable with but, would clean the data up a lot and resolve some of the myster
you would still not count all the carbon that was part of stuff that went in your mithocondria, you exhale that, around 270g/day. So the only way to keep track of that would be to use radioactive carbon in the soylent or something and collect all your exhalations
Asstronaut asscream D:
i was thinking the same thing, but i think ben probably wants to space out his rounds of soylent brown diet. soylent brown is poople
@@seanshomeshop325 Actually, it's peepoo but he only used the poo part in this -excrement- experiment.
>Puts out 15min video talking about E.coli
five hours later:
>Frankly this is way more playing with shit than I'd be comfortable with
"I did a sloppy job doing the lamination" he says holding something that looks optically perfect.
There where some bubbles I think. You can see them when he holds the composite at an angle.
according to Peter Brown, you'll have better results curing in a pressure pot, even if you skip the vacuum offgassing
He's just messing around
Been watching your channel for years and never commented. Just wanted to say thank you. The amount of time you spend on a 30min video must be insane. And its highly appreciated. Thank you.
15:05 Try a U shape groove (not too deep) for holding the silicon seal in place.
Ideal is when the glass is pressed firmly down and barely touching the metal holder, that way the gap of exposed silicon seal to the burning environment is almost zero and the seal will last much longer.
This technique is used in small (50a70cc) 2 stroke watercooled bike engines (pocketbike etc...)
This is one time I don't mind our Patreon dollars going to waste 😎
holy shit you're alive?!?!?
ba dum tss
I see what you did there
Fitting, considering the image on your last vijeo, 2 years ago.
Fecal waste
I love how it could´ve been a clickbait thumbnail but was not, thank you
Agreed. Not enough credit is being given for the restraint shown.
The true power of Patreon
Backyard scientist youtube is great because of that
Thank you for doing this! This has bugged me ever since we had to do calorimetry in high school science. I asked about the difference between flammable caloric content and what your body can use, and basically got told to shut up and burn my peanut so we could get on with it.
@Stay EZ My Friends without schooling you would be a vegetable with no knowledge on anything. just shut up
@@capekraken2672 not really true tbh, for basics absolutely, but academics exceed in killing passions. if there's anything your actually interested in, from my experience, its better to do it yourself. which sucks!
@@albertogregory9678 sure, but I would not go as far as stating it is a passion killer. Even if you absolutely know your passion (which is more rare than not for high schoolers), you need to know how to do other things than just your passion. As well, school (at least here in Australia), you can choose which subjects you do and which ones you want to excel at.
@@capekraken2672 I disagree. I never went to elementary school or middle school but had a 4.0 gpa in high school
@@neil963 I find that extremely unlikely. Did you have home schooling? If not, you must have worked extremely hard to catch up. Even so, you still had schooling which was not my point
You are a gem. Your Patience and dedication towards scientific experiments is admirable. Love you. Keep going 👍👍
I TRUELY LOVE YOUR VIDEOS!!! Speaking as a person who uses a wheelchair and has a severe physical disability that keeps me from being able to use things like lathes and many other things I see you using all the time, your amazing videos keep me from going crazy thinking of all the things I wish I could do but cannot with my disability. The world really needs more people like you in it!!!
❤️
So you measured the flammable-calories per gram of each, but, if evaluating efficiency, wouldn't you have to also factor in how the amount that went in corresponds to the amount that went out?
agreed...my understanding is with soylent there is very little waste product.to cross multiply solving the correct fecal load to test would be vital.
That is a perfectly normal way to look at it. But knowing that factor presupposes that you know the efficiency number that is attempted to be derived.
The alternate method is then comparing known mass and then seeing what energy remains in that mass. The end result is the same because if your gut is ~20% efficient (16K / 20K), then if you put in 0.5 grams, you'll get 0.4 grams out. That is equivalent to 20K Joules in 0.5 grams in and 16K Joules in 0.5 grams out.
@@Michael-OBrien But what about the mass that is lost via exhalation? The carbon in the food we eat is what ends up in the CO2 we exhale, yes?
@@drdca8263, I’ve favored this explanation: ua-cam.com/video/vuIlsN32WaE/v-deo.html
Yeah, I was surprised this wasn't mentioned.
Best channel in YT
He has one of the best science channels on youtube for sure
By far! Support it on Patreon!
The calories per gram is probably much less relevant than total grams input vs total grams output. You should be excreting a significant amount of mass as H2O and CO2, so for every 100 grams you consume, you likely only get half of that out in waste (totally made that fraction up. Anything between 30% and 80% seems plausible). Also, ion content (Na, K, some Mg and Ca as well) will be eliminated mostly through urine, and should be relatively low amounts in stool. Chemically, you would still expect stool to be largely the same as the food input in terms of carbon, hydrogen, nitrogen content, and comparable ratios of the assorted chemical bonds common to most organic compounds. Really not at all surprising that it's so close.
Would be interesting to find out the nature of the residue that was left after the burning in relation to total input-output, especially for 'artificial' food like this powdered stuff with nutrients added and subtracted.
Yeah, eating a gram of soylent almost certainly doesn't result in excreting a gram of poop. This is why food studies are very difficult - you have to completely control all intake and measure all output, which often requires more control over a human test subject than most ethical boards are willing to allow.
The mineral deposits after the poop burning are an indication of this ratio - the tiny amount of minerals that weren't absorb were present in the poop, at levels higher than in the input. It might even be possible to use this mass change to work out the ratio of input to output, if you go through all of the inputs and work out which would become a gas and which would become a solid after burning... Probably not accurately, but good enough to get a rough estimate of the ratio.
To add another aspect to this, how can we be sure that the fecal matter is just what you ate, and not include a mix of dead cells/other parts the body no longer needs?
Fecal matter includes a lot of dead bacteria, undigested plant stuff, fat (2-15% of the solid part), 2-25% protein. Outside cells just flake off, and epithelial cells (insides of the stomach, intestines) also count as outside, so yes, they are also in the poop. Internal cells usually undergo aptoposis and macrophages (literally means large eater in Greek) "digest" the remains. (See also phagocytes, the cell-eaters, and efferocytosis, undertaking-of-cells or cell burial.)
Basically neighbor cells recycle what they can, and empty the rest into the blood, then that finally gets to the urine.
@@iccuwarn1781 It's not just what you ate, for sure. Also, your body adds a ton of stuff, enzymes, acid, bile to neutralize the acid, and a constant layer of mucus to protect the inside of the digestive tract from eating itself away. I think dead cells are largely reabsorbed, except for bacteria that die in the intestine, and the skin that sloughs off the outside (and into the digestive tract, which is also kind of the outside, topologically speaking)
I learned more in the first 90 seconds about calorimetry than have in the rest of my life. Your videos never miss.
"The process is basically making astronaut ice cream. It's exactly the same." I no longer like astronaut ice cream.
did i miss it somehow? where did you measure how much mass input results in how much output. there is a substantial amount exiting your body as co2 or pee.
you'd need to monitor the output weight until it stabilizes over time to get a input to output factor
btw. goofy face cover ftw
please don't forget to clean the dryer before making new icream 🤣
He measured the 5g of soylent and 5g of poop. The difference of calories between them is the result.
That's a good point. If you take in 1kg of food with Xcal per g and poop out 100g of poop with also Xcal per g doesn't mean you didn't extract any energy at all. It means that you've extracted 90% of the energy. Input and output weight ratio is important
And all the nutrients used to grow hair, nails, shedding skin, etc.
@@TimLF Good point, but I think that would be a very small amount. I mean, how many hairs/skin cells/whatever do you grow over a week? Not a lot probably
@Anifco67 That's what I mean
"How many calories are in a turd?" This is the type of question that keeps me up at night.
Here's a video idea: You can use your mass spectrometer and some isotopic water to measure exactly how many calories you've burned in up to about two weeks. It's called the "Doubly Labeled Water Test".
The idea is that you drink some water with a safe percentage of both 18-O and 2-H in it (get by mixing partial 18-O water with partial deuterium water, each not terribly expensive) and 15 minutes later measure the baseline ratio of 18-O to 2-H in your urine. After however many days, the 18-O and 2-H will have diminished an equal amount by leaving the body as water, but only 18-O will have been incorporated into exhaled CO2, which by definition is a direct measure of calories burned. So at the end of that time period, the new ratio of 18-O to 2-H in your urine tells you exactly how many calories you've burned in that time. And all you need is the isotopic water and your mass spectrometer.
Very cool idea! But it just measures the energy you've burned during the time of measurement. Burning of fat already stored in the body as well as new deposits can not be monitored this way.
I'd rather stay on his track measuring the source of energy instead of it's outcome as he tried. But he didn't account for the loss of mass since digesting means taking up the nutrients (and finally breathing them out as CO2). So i'd correct for this error by adding an undigestable stable compound not being absorbed by the body added to the soylent to correct this flaw.
Doesn't most of the oxygen from co2 come from oxygen in the air?
@@hetsmiecht1029 Some of it, but CO2 is a waste product of our metabolism.
you're my favorite youtube channel period. every single one of your projects is astoundingly high quality and fascinating. thank you for creating these videos for us, this is the reason the internet was created.
As may have been mentioned, a change in diet can quickly change the bacterial ratios in the gut. Carnivore diet proponents often report their first week of stools being very black and runny, and nutritionists have responded saying the bacteria responsible for digesting meat proteins are increasing in quantity while those for vegetable matter are significantly decreasing. This shedding of dead or dying gut bacteria from the intestinal lining could explain the higher caloric readings from your fecal sample.
Fascinating experiment!! Man, I love this channel!!
*Thief steals items from garage*
Ben: *Immediately develops concentrated, distilled essence of poop*
Well collect a bunch of it and send it to Mark Rober, I'm sure he has a use for it around x-mas.
He is always looking to improve his contraptions.
NurdRage actually did distill essence of poop years ago.
@@5roundsrapid263 Skatole, you mean?
@@5roundsrapid263 Link?
That episode was hilerious. The „eau de toilette“ bit had me rolling.
Did you catch the "bombs away" at 24:57?
"eau de toilette by choco channel" i.e. soy-lent chocolate.
@@PKMartin May as well be where the name comes from, who knows?
2:45 The "one" is a magnificent touch
Agreed. If anyone else ever tells me engineers dont have humour Ill refer them to this timestamp
He was thinking of making it the thumbnail... The question is; why didn't he?
@@rkan2 a mystery to be solved by future generations
@@maibster mistery
What is the joke or reference I am not getting?
Hi, a great experiment. I think that there is a more complex issue occurring here. Fecal matter consists of the residue of digestion but also contains the bacteria of the gut flora that are expelled, and the remains of the gut mucosa that is abraided as the bolus passes through the intestine. Additionally, there is the product that is secreted by the liver as a byproduct of blood cleansing and replacement. altogether "food for thought" Thanks for the fun, Richard
Liar
The fact that you went to these lengths for real world science has alone earned you my sub. Looking forward to working through your back catalogue. Sometimes the algorithm gets it right...
Not sure if I missed it somewhere, but aren't you comparing apples and oranges when comparing the energy density of the input and output matter like that, in that a certain amount of input might result in a much lower amount of output as the digestible bits are converted into water and CO2?
To be fair, he did say he was just screwing around.
If he collects and dries all output, over long enough time to average out the fluctuations, he could establish the dry matter input:output ratio and get a more meaningful efficiency value.
@@4hodmt He'd still have to take into account any non-water weight gain, but this could also be a way.
@@JustOneAsbesto 24:46 - He did say "we", which in my opinion implies the audience as well :D
He could used an inert non-digestible standard that could then be measured and used to determine the mass to burn in the calorimeter. No sure what or how (maybe mass spec) and I can be suer it would add significant cost/complexity
Your body also continuously disposes of dead cells, mostly dead blood cells which have a high calorific value. That brown color...iron.
Awesome job on the experiment.
Right. Fecal matter is more than just what food you didn't absorb.
Yeah that is going to change the output if your body isn't working the same way 24/7... But I guess it wouldn't suddenly change by that much if the input is constant.. Except if you constipate for the duration of measurement, I guess.
The brown color is not iron, but instead bilirubin from breakdown of heme. Iron is far too precious in the human body to excrete willy-nilly: there are in fact no identified ways in which the human body can get rid of iron intentionally.
@@RBuckminsterFuller and that iron is removed as part of the breakdown of the heme complex.
@@billsmathers7787 Thank you!
Someone who gets it. 💡
"Put on safety goggles"
*Pours water all over electrical equipment*
lol - Lockdown Fatigue Syndrome 20:42
I gotta say that this is your best video yet. The fact that the entire journey is to test the human system is interesting, and having to learn about an entirely new device on the way there makes the whole thing amazing. Great video. Thanks for sharing your love of exploring with us. Trurhfully, since your passion is genuine, you could have just never uploaded anything way back at the channels beginning and remained perfectly satisfied. I'm really glad you did.
This was an awesome demo / experiment. I remember reading the details of calorimeters in university chemistry class, many years ago. We did the math, but I never understood any of the engineering behind how it would actually work. This was super cool to see done in real life! Thanks!
Next on Applied Science: Keithley's new conformally-coated benchtop multimeter...
IP67 rated source measure unit, I need one!
You’re assuming that 1g of “input” produces 1g of “output” which is likely not true...
Exactly this. You exhale the "burned" carbon as C02 as you breathe, you don't defecate it out. Most of your fecal matter is bacterial colonization of the remnants that were not easily broken down into macronutrients and absorbed by the body.
I was just about to bring this up in a comment.
It seems intuitive that it would take multiple grams of food to produce one gram of solid waste.
Some of the mass difference ends up as metabolites in urine, some ends up exhaled as CO2. I'm just not sure what the ratio is.
@@MysticalDork Isn't that a point? If You exhale CO2 that means that it was digested and absorbed by human body. Everything "undigested" will end up as a waste.
@@Krawacik3d Still doesn't change the input-output ratio issue. If you eat 3lbs of food, but only excrete 8 ounces, even if they're the exact same energy density in the calorimeter, you're only leaving behind 1/6th the energy of the input in the output.
@@TrumpeterOnFire That's true. Now that I think about that measuring total amount of energy undigested should be easy knowing it's density and total weight, maybe Ben will make follow-up video regarding this.
Amazing engineering setup, but I think there is a little lack in microbiology plan. Poop is mainly consist of dead bacteria and some fibers. That bacteries were responsible in food digesting and the total process is too complicated to be resolved like as simple input/output example. But overall this is cool demonstration.
His experiment is a literal application of the first law of thermodynamics, his body being the control volume, and the efficiency calculation is applicable. Whatever energy was transformed by bacteria, it could not have been used by his body if it was still within the pooped bacteria.
@@homemdosaco2000 There are still considerations like the balance of bacterial biomass still in his body. It may fluctuate. More sampling over a long period of time along with body weight tracking might help trace possibly error. I also wonder if he used any stored fat during the experiment, or measurably lost any weight.
Agree that weight change can skew the calculation. Bacterial mass would come to an equilibrium with the controlled diet, but I have no idea how long that would take.
However, I stand by my previous statement that whatever energy was pooped, did not contribute to his body functions.
@@homemdosaco2000 it's literally that simple, yet the comments insist different, demanding things that are empirically impossible to control for. The mystery has been solved. 'calories in calories out' is only 25% accurate
I guess this means he needs a control where he eats nothing for a week ... 🤔
Hey Ben, I've had similar design challenges at work when working at high temperatures. Sizing the metal pipe ID for a close clearance fit and adding another step farther back where the plastic window begins and placing the O-ring there will prevent it from burning. Any hot gasses from the flame will cool flowing thru the narrow gap to below ignition temperatures before reaching the plastic and O-ring. Love your channel, keep up the good work!
Sir, you are a genius. I love your attention to detail, and I love your channel. Thank you for sharing your knowledge, your journeys, and your triumphs.
This is awesome, and deeply into mad scientist territory.
Hey Ben, interesting video as always. I do wonder, did you correct for total weight on the input and output side? If your body takes up a certain percentage of the input weight, only the remainder of that percentage is truly lost. If the total output weight is not the same as the input weight a comparison of joule per gram does not make sense right? Could that be the missing piece of information?
you would need a none consumable substance, in the input, to test in output. that would quantify the food it represented
@@themadrobot he could measure the ash content of both materials to get a rough estimation, although you would probably need to purify the ash before measuring it to account for soluble substances like salts getting lost in other ways. This would be very complicated though.
Or simply weigh the dried soylent and the dried output of a given period, and compare the calorific values of the same proportions.
@@lucassu95 that first came to mind but, the prospect of freeze drying so much as a few days of 'material'
24:49 I think you have the UA-cam channel who most closely toes the line between screwing around and publication quality 😂
The only difference between science and screwing around is when you do science you write it down.
Thank you for spelling "toes the line" correctly.
This man makes a super in depth and scientific video that is also watchable. Well done sir.
Incredibly fascinating! I agree with a lot of the comments saying that the digest system is far more complicated than the simple input/outputs you used. But I didint know that when I watched this! Please keep up with these experiments. We may not get many solid conclusions but we will all certainly learn a lot more about human digestion.
We're all united on the warm cozy feeling we get when a new vídeo comes out
W.r.t. the burst/leak thing at roughly 7:11, the determining factor of whether or not the plastic will also burst is if the speed of sound in the containing material is faster or slower than the speed of sound in your contained fluid. There was a silicon wafer plant somewhere that had a pipe full of silane explode every pipe in the plant because the speed of sound was faster in the pipe wall material, so the pressure relief wave in the silane was always slower than the pressure relief wave caused by the crack in the pipe.
[edit]: related paper that I haven't had time to read yet: www.icheme.org/media/10230/xv-paper-15.pdf
It looks like that it isn't the speed of sound in the pipe material, but rather the crack propagation speed, and there's some more complicated math going on than I initially thought. Still an interesting read.
Burst? Isn't it burning in oxygen rich environment like he said? The seal will be in contact with the oxygen.
@@rkan2 True, but that's a different failure mode. I'm referring to the pressure being specifically too much for the window. The seal burning through is the sort of problem that could've been solved with a correctly sized O-ring groove. 😉 Though it should be a fire-resistant material anyway given the environment.
That is a great Calorimetry setup! Your window making skills are legit. My first one involved a banana that I stabbed toothpicks into, placed foil on top of them, and a piece of popcorn under the foil...resting on the banana. Put some water on top the foil, burned the popcorn, then measured the change in temperature. Safe to say yours is a LITTLE bit better of a setup. Nice work!
ua-cam.com/channels/SF5QS3jO8MaUiNIUnkhcFg.html
Smart thinking tho 👍🏻
Really cool video! Though I was under the impression that a large amount of the carbon we excrete is via respiration (2.3 lbs per day if I recall correctly). So factoring that in would probably be pretty important.
By definition this is not usable carbon, and it's excreted just the same in the case of combustion.
@@petros_adamopoulos What? Of course the carbon we exhale is usable. Not after being exhaled but before and it should definitely be accounted for in this balance.
@@petros_adamopoulos by definition, that carbon WAS useable carbon. The CO2 from your breath comes from the cellular respiration breaking down energetic molecules your body got from food.
As always, great video! The missing key in this experiment, as others have pointed out, is fuel weight compared to ash (fecal) weight. You really have to perform a chemical analysis of both the food as well as the fecal matter, sort of like a nutrition label for poop. Yeah... I think I won't go any further with that train of thought.
I totally geeked out on your construction elements, starting with the composite window! Right as I thought to myself you should use a UV cure resin, I saw you waving the flashlight over the window. NICE! And I love your idea of cutting a gasket on a lathe with an Exacto blade! I may have to use that one!
Thanks for the great video! Cheers!
This is a fascinating subject. I've always suspected calories from alcohol does not accurately portray digestible calories. It would be interesting to see an experiment with that premise. Thanks for the excellent content!
Oh thank god, someone who actually know something! I've thought about this very subject many times. I really appreciate seeing all the tips and trick of getting the experiment off the ground. Thanks for the video! By the way, for anyone working with high pressure oxygen, make sure you never allow hydrocarbons to come in contact with the oxygen and always use copper lines to transfer the O2. Stainless steel will become flammable at about 5 bar (75 psig ). Also, if you use PTFE tape, make sure it is certified for oxygen service. Oxygen certified PFTE has no oils that can burn. I have investigated several O2 explosion in the past few years where people have not headed these precautions. As to the calorific balance, how much input mass was there vs the output mass? E.G. If you ate 200 g of Soyulent and had 100g of fecal matter ...
Ah, your own version of a This Old Tony's "Shootin' the Poop" episode.
"Kill it with fire" style
Nice video man! You raising garage science to new heights. Please do the macro nutrients individual contributions to usable calories.
Nutrition science is certainly one of the most contentious topics in physiology and medicine, going back to fundamentals like you habe is refreshingly straightforward...
I have asked myself this very same question countless times - thank you for finally answering it!
I wonder what my neighbor is doing, smells like hes burning shit over there.
He distilled the essence of this smell in a few droplets. These droplets are the ultimate weapon. Ask a skunk for verification.
@24:25 "concentrated, distilled, essence of poop" This man made liquid ass. LOL
Nile Red: Made From My Own Pee
Ben: Hold my Soylent...
Dear Sir Ben, This is Simon, a Engineering student at Rice. Thank you for the fun and detailed introduction about soylent and calorie test. I also like soy, besides spirulina, another plant-based food powder. Happy New Year.
This is what you call dedication to science, folks! Not going to lie, this question has crossed my mind as well but you actually went about answering it!
I’m a food scientist specialized in food chemistry. Let me know if you need any help with the determination if macronutrients! It would be great to contribute to your videos!
Soylent produces very consistent "results" :) I'm a food scientist too. Reading nutrition facts labels was one of the reasons that made me interested in the career. I really enjoyed the college class where we analyzed the nutrient composition of a food of our choice. I chose a Burger King Whopper :) It was so fun liquifying it in preparation for freeze drying, then having a taste of the whopper powder afterwards. It tasted great! (retained much of the flavor) Then extracting all the fat with hexane and nitrogen for protein. The lab manager ran the bomb calorimetry for us when we weren't around, so I never saw it in action. Finally, I now have!
@@DFEUERMAN were the nutrition facts correct or do companies lie?
"Aluminum window" made me chuckle.
Hello computer!
Surprised he didn't make an actual clear aluminum window. Yes they are a thing before you go there
Everyday before work, I put a rock in my boot. At the end of the day it feels so good to take it out.
This pipe bomb 😆 you made looks a lot like the regulators I build at work. We use 2024 aluminum, 7075 aluminum, cda 360 brass, Viton o-rings, Kel-F plastic and 303 stainless steel.
And yes, Buna burns like a fuse in oxygen rich environments. Viton and silicon melt and burn, but buna/nitrile is almost explosive.
Wow! It's about time someone asked common sense questions like this. Wonderful video! Thank you so much!
I was just amazed when you cut those gaskets on the lathe, that’s a brilliant idea. An idea for a flame proof gasket could be a copper ring or maybe flexible graphite
I was thinking some kind of copper alloy as well, a soft brass or copper that can deform ever so slightly under the clamping load
Copper gasket is brilliant to some. the mechanic is like "this should have been obvious".
Copper is a standard material for vacuum gaskets
@Paul Skaar not sure about grafoil where there's fire and pure oxygen at high pressure. I'd expect some of that to be combusted. but maybe I'm wrong on that.
@@samalbury9183 i suspect it probably dosen't make a difference here with using copper gasket in vacuum vs hyperbaric.
Does copper cold weld in vacuum conditions?
"by the end of it food tastes so good". raving review, i see.
Please switch the thumbnail of this video to the clickbaity one at 2:45 - it truly is a masterpiece xD
This is super interesting. I have always wondered about how little the human body can actually live on, and if it just changes input and output based on individual metabolism and nutrition conditions. One problem that I can see, and you probably have as well, is that I don't think you can compare grams for grams on input and output. Input could have ~5% fiber, where as your output could have ~25% fiber due to the body unable to process it and therefore concentrating the flammable calories in a smaller amount of waste. In this case you would need to get a ratio of the amount of food turns to actual solid waste, since the body has other processes that remove waste, breathing and urination.
There is so much going on here. As always, so much information to process in your projects. Thanks for sharing.
great mind, and ability to pursue these things far beyond the average person. thanks for your efforts!
This is awesome. Thank you for exploring this as it's an area I've always been super interested in. We hear diet is simply a matter of "calories in / calories out" as if humans are some 100% efficient bio machine able to absorb all forms of calories equally. It just doesn't make sense and no one can convince me that human bodies supposedly do the same thing with 100 calories of sugar vs 100 calories of protein. Food only stays in our system for so long and our ability to absorb and digest different food components has got to be variable which means depending on what you eat your efficiency is going to differ. There are probably tons of variables at play depending on the specific macros of the diet you consume.
There're stories of people losing weight on a 2000 calorie McDonald's only diet and while it's true that person did lose weight on strictly counting calories I feel we totally miss the rest of the story and why. Could this individual have lost just as much weight eating 3600 calories of boneless skinless chicken breasts and broccoli? etc... super interesting, thanks for playing with your poop
And remember that same ignorant arrogantly and totally wrong attitude as the calorie in calorie out goes for the entire health industry...
I lost weight at 14kcal/day with moderate exercise generally just matching macros and completely ignoring how I got them, whether candy or fast food who cares. Growing up I've been generally in this a mode where I'm eating as little as possible, in which can totally maintain weight at 200-800/kcal a day. (As an average of 1 big meal every few weeks) But, if I eat regularly, such as any time I tried to get healthy, my body would just ramp up it's metabolism and be more hungry all the time, ramping up to generally 6kcal/day at sedentary assuming I'm just eating every day. The longer I power it, the more it starts burning, I swear, I can't maintain my body at full stroke like a reactor heating up. I'm generally always eating every few days to avoid getting too hungry and eating too much. Up until about 25 I never had more than 5% body fat despite....Hell, I could do 25kcal mcdonald diets and regularly ate 10kcal sedentary fast food with no impact, just living daily with an unhealthily low level of body fat.
So this one time I was exercising. I was matching macros at the extreme bulking ratios and I was still losing weight, so I just decided to eat as much as I felt I needed to which ended up being 2-3x the extreme IIFYM calculator recommendations. When I finally started gaining weight, I was a 130lb kid eating literally 4-9lbs of food every day, half in fish and half in junkfood. Affter 2 months of eating 14-24kcal a day like that and my body capped out at 145lb... 15 extra pounds(0% fat, so not a bad job...just felt like wow, that much work to gain that little? Eh...not really worth the energy) and always eating and I just couldn't put any more weight after that. I got so tired of eating so much, spending 70% of my day working out and eating. I had to live singularly for my body if I actually wanted it to go anywhere, wouldn't even have time to stop chewing :/. So, I lost all the weight in 1/2 the time it took me to gain it and with 0 the effort. On the other side of it is that it's possible to fast for weeks with ounce losses when at equilibrium too, pretty wild. So, trying to push my weight up +10lbs takes an exponential amount of input so much so I cannot actively do it. And trying to lose 10lbs is pretty impossible too. Really makes you wonder what's going on e.e
But yeah, I've eaten pounds of grease daily for months, with no appreciable effect except for the rumbling in your heart growing in intensity, like your blood's cholesterol is actually perceivable due to it's viscocity which causes high cholesterol blood to "rumble" more and thus you can feel the veins vibrate your skin more. I could be crazy, but every time I eat high satured fats and lots of junk food, It builds up, even you are more lethargic as if it's because it's harder to get nutrients around with fat kid blood...idk. Just years of anecdote. As a kid it built up way slower, as an adult I swear I have to be careful of grease. A few heavy days and I start noticing, vs teenage years and months without impact. Anyways a result of that sort of hypochondria, I have a pretty natural limit on eating just pure fats nowadays, I don't mind a meat stick here or there, but I'll start feeling like...my heart just working harder, the rumbling of your veins more, truly disgusting sensation...Gives me the willies e.e
@@GRAYgauss That was an interesting read. My brother is also afflicted with whatever genes are required to eat tons and stay lean. He hates it but I sure wish I had gotten those genes too. I'm the opposite. I have to fast and stay well below recommended calorie intake in order to maintain or simply not gain.
What is also going to offset these readings is that your body has a very long term storage. Combined with that it is constantly breaking down its own cells, primarily blood cells, results in fecal matter containing many elements that would not be in your nutrition from the past week.
Broken down body cells don't go into fecal matter, they are transported with lymphatic fluid and blood and end up in urine. However chemicals reused in digestive fluids such as spit and bile do get mixed into the digestive tract and may end up in fecal matter if not reabsorbed along usable food chemicals.
Exciting ! I want to make my calorimeter now... 😅
HAHAHAHAHHAHAHAHAHAH....my thought exactly.
If it's a bomb calorimeter, and not some simple coffee cup one... I would strongly urge you to be far away from it on it's maiden voyage.
There's a very fine line between a bomb calorimeter and a pipe bomb.
But don't let danger stop you from doing. Do it but just be safe homie.
I just poop out on the road and burn it there, less messy
You deserve more views, my friend. Love your approach.
This is a great demonstration of calorimeter bomb. I've learned about the bomb in thermodynamic class, but never seen it work in real life. Thanks you !
"The only difference between screwing around and science is writing it down."
- Adam Savage
So true!
I should have taken more notes over the last 20 years.
Ugh, I hate to be *that person*, but the quote is actually credited to Adam Savage's ballistics consultant, Alex Jason. Adam overheard him say it after a tough shoot and stole it (with permission) to say on camera. :)
would be a better quote if science had actually been defined, but after 200 years of attempts I guess it's been agreed that it's not something distinct.
@@senselessnothing I think what defines science is that it makes falsifyable predictions and theories. And it is methodical. As long as you're writing down your observations you are potentially providing data for testing those predictions and theories.
@@kwinzman what you're describing is an old interpretation by popper and such, it's failed pretty miserably over the decades and was the last big interpretation out there.
ever since i learned that ICEs are about 20% effiecient in middle school ive always wondered whether i have a better fuel efficiency than my honda bike
Running 10 miles burns 1k calories and a gallon of gas is around 32k calories, people get 320 mpg if we could eat gas. Very roughly speaking.
On a pedal bike, you get about 1/38th miles per calorie. So if you ate gas, never slept, and never did anything else you could go 853 miles on a gallon. But you'd only be going about 15
@YeYaTeTeTe you can't tell me what to do
0:10 NileRed beaker!
NileRed does that thing at the end of his videos where he scrolls a list of Patreon patrons. AppliedScience has been a patron of his for a long time.
Ben also sent the supercritical CO2 chamber which he mentioned in this video to NileRed some time ago
This was fascinating! The best part of seeing the waste accumulation of mineral salts nodules and other non-digestible fibers expelled as compared to the input of viable nutrients. The human body being an efficient storage battery of nutrients until they are consumed as needed.
This guys channel is such an addictive rabbit hole!!
"I'm not fat, I'm efficient!"
Too bad you couldn't find a thick quartz or borosilicate glass plug for the viewing window, but yours seems to work well. I love the method of making a silicone gasket. Always unique videos! A++
All of these materials would break in a very similar way to glass. He did the right thing by using a very ductile material.
some materials can take a lot of sustained pressure, but i'd worry a sudden change (like underestimating how fast it would burn) might shock it into shattering regardless. his solution is probably safer overall.
I prefer your videos
the fact that glass has a statistical failure rate is really interesting
so that means you can't trust it will break after 1000 uses, but instead that each use has a 1 in 1000 chance of failure?
it's not like that. if you don't exceed the ultimate tensile/compressive/shear strength it shouldnt fail
@@krzysztofbroda5376 He explained it very poorly, glass is super complicated
Runforitman. This is generally correct. Architectural glass (e.g. window Glas) is typically closer to 7/1000. You can manipulate the ratio by “massaging” the material (e.g. grinding and polishing edges), but won’t change its inherent statistical nature.
@@krzysztofbroda5376 not.
This may already be in the comments below but here goes: YEARS ago in p-chem lab we just used (if I remember right) sodium nitrate in excess. For anyone trying this at home, this makes a much easier approach than using oxygen gas. Great video BTW.
I had this idea but never the means to carry it out and I am so proud that you did this. Amazing!
2:45 Ben, you're really missing out on UA-cam clickbait potential ;) (though we're all glad you don't indulge in that stuff). Great video as always.
13:42 also made me laugh out loud XD
That clickbait thumbnail reminded me of one of his earlier vids about why he doesn't do clickbait thumbnails (and provides an example, similiar to this one)
nice callback :D
@@__dm__ Do you happen to remember which one or enough to give some keywords to search for?
For some reason I find the "?!!one!* Hilarious :D
@@Biped 😅 I’m not sure what you mean. Are those extra characters around the word “one” showing up for you in my comment?
@@dowdayjing8442 yes, they do. Maybe I should have explained a little: in clickbaity videos the title often includes a lot of !!!!!! However if you slip of the shift key while doing that you have !!!!1!! for example. It shows how sloppily it was done. But somehow accidentally getting a literal "one" in there would be tricky and quite funny :D
"distilled essence of poop"
NileRed wants to know your location
He is probably too busy getting ureum from his own urine 😂😉
@@SerumCRM114 Well yes... hah.
But he also has a skatole video that literally says "The esscence of poop" in the thumbnail
Question for thought, but isn’t the human waste condensed too? Its not 1 gram in = 1 gram out - what is the actual ratio of mass in to mass out? That also may shed some light on the efficiency numbers.
I guess he would need to weigh how much he consumed, and how much he peed and pooped out, and calculate ratio. Good point!
Results surprised me, and though me a lot. Somehow my brain was always just assuming that there is a "fire" in the stomach that would pull out >90% of the calories. This experiment is simply awesome and I will perhaps never look at the nutrition labels the same way again!
I like how you describe the process of success and failure. The whole time I was speaking aloud, what if you do this, what if you do that. Very fun and informative.
Huh, I wonder what the residual poop nodules are. Calcium, manganese, and phosphorous compounds maybe?
phosphates and sulfates seem pretty plausible. calcium sodium and potassium phosphates and sulfates wouldn't be gasses after burning, and have high melting points.
Just concentrated minerals. Basically minerals from food that were not absorbed present in a much higher concentration from the input Soylent.
Alternate title : The sh!t we do for SCIENCE! Burning questions answered!
underrated comment xD
Most people burn their poop on front porches, Ben loads his on UA-cam.
Thank you very much for the hard work you did to do this. It is impressive. And it shows how hard it is to get new science correct. Others have pointed out the flaws, so I’m not going to do that. I’ll guess that the body tends to be able to absorb 95% of the nutrients. Intestinal flora gets most of the remaining. If we weren’t getting nearly all the usable energy out of our food, evolution would have lengthened our small intestine. Here are some facts that I remember. Almond paste is fully absorbed, but almonds aren’t due to inadequate chewing. Feces includes fiber that was eaten, intestinal flora, and cell components-I have no idea the heat energy each has. Improvements to your methodology include measuring solid inputs and outputs, weighing urine and analyzing urine composition to calculate nitrogen loss, estimating respiration and calculating carbon loss, and estimating skin slough.
We use to make bio fuel out of poop and we realized we were getting massive amounts of iron slag developing on things during high temp burns, it was the iron in the blood that was in your waste. It was very surprising how much was in waste and how much slag would build up on things.
Great video, very interesting as always. I was so surprised to see such a basic mistake made though of comparing 'grams to grams' of soylent to dry poop. Obviously if you ate 1kg of soylent and pooped out 100g of poop, the poop could even have greater calorie density from the indigestible fibre, so it literally tells you nothing?
Surely you'd have to clear out your system, eat a bunch of soylent, clear out your system again, and measure that. Even then, you'd have to take strong antibiotics to prevent the results being contaminated by biomass, and that would be awful for your health.
Eating soylent for a week in the name of science, now that's dedication
yeah man i couldnt bring myself to eat people personally
Collecting and burning a week's worth of your own waste for an experiment? Welp, it's official - Ben is indeed a real scientist.
I have to say this: your face doesn't LOOK like that of a scientist, so your clear way of thinking, speech, research and presentation both surprises and amazes.
That's a weird compliment lol
@@lucasg.5534 I may not have expressed myself clearly. What I meant is that if I met this guy on the street, I would have thought that he was just an "average Joe" without any advanced knowledge or skills, he just has that look/vibe.
But when he starts elaborating and showing his research, it is clear that he is an intelligent and knowledgeable scientist, which simply doesn't match his appearance.
Looks and first impressions can be very deceiving.
the sacrifices you have made for science are greatly appreciated