Applied Science - 2021-02-23
"200 Calories" on a nutrition label doesn't describe the total flammable caloric content. I explore the differences between digestible and flammable calories using a homemade calorimeter with glass windows. Pressure sensor: https://www.digikey.com/en/products/detail/te-connectivity-measurement-specialties/M5842-000005-10KPG/7592854 Schedule 160 pipe on McMaster: https://www.mcmaster.com/7733K259/ 32 ga nichrome wire: https://www.amazon.com/gp/product/B07DL4DSWD/ Power supply (used for ignition wire): https://www.amazon.com/gp/product/B07SS77N7K/ Keithley 6.5 digit multimeter: https://www.tek.com/tektronix-and-keithley-digital-multimeter/dmm6500 Tek MSO 4 series oscilloscope: https://www.tek.com/oscilloscope/4-series-mso-mixed-signal-oscilloscope Soylent: https://soylent.com/ Hmm, I perhaps mis-remembered that 20% stat from Sally Le Page's video: https://www.youtube.com/watch?v=92F_yocEchA There may have been another source that indicated the 20% number. This will probably show up in my future video on macronutrients. Support Applied Science on Patreon: https://www.patreon.com/AppliedScience
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.
@Ned Welch 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.
@Ben Kucenski 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
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...)
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.
This is one time I don't mind our Patreon dollars going to waste 😎
Time enjoyed isn`t wasted ;)
Still missing Your excellent videos... watching the same ones only goes so far ;)
Jokes aside, I hope all finds You well, and I want to thank You for all the great content You have put out.
Best regards
Yay, you’re still around! Where ya’ been?
Missing your videos!
Good to see you around!
What are your plans?
but Soylent is people!
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!
You are a gem. Your Patience and dedication towards scientific experiments is admirable. Love you. Keep going 👍👍
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
@GRAYgoose124 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.
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!
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.
Agreed. He’s also missing body weight loss or gain during the period, in which some body fat might have been burned, not the Soylent, and fat waste product is measured instead.
@homemdosaco2000 Body weight was mentioned in the video, thus not controlled
Ultimately, isn't any energy used by the bacteria within your gut going to become heat? And also wouldn't that generated heat be heat that your body didn't have to produce to keep you warm? Although, I guess you would also have to consider other byproducts like methane in farts.
@homemdosaco2000 Nope. Most of the ingested mass is lost by respiration. Carbohydrates are called carbohydrates for a reason. Of glucose literally NOTHING leaves your body through the back end.
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.
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!
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.
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!!!
❤️
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!
Smart thinking tho 👍🏻
This video is absolutely fascinating. I'd like to see more tests, and ones from multiple people. Let's find some averages and some stats on food labels!
Amazing project and video, thanks for making and sharing this!! And by the way that laminated window you made actually looked great.
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.
"The only difference between screwing around and science is writing it down."
- Adam Savage
@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.
@albu obscure I think Popper was hugely successful. Why has it failed in your view?
@kwinzman Alright I will try to very briefly mention some points. One would be precedence issues, so since no hypothesis is ever verified, having asked a question, when does one ask a second one. In a similar vein when you apply the theory itself to be evaluated through its own methods, you find that it puts itself into question in many cases, as most science historically, say fourier's stuff, had no resemblance to what popper would make you believe. Another point would be that the "empiricist" methods he would like are all rationalist in nature, be it mathematical or statistical, as those subjects have offered more failed scientific theories than successful. Another one would be the fact that in mathematics constants such as π are irrational, ie have "infinite decimals", which if you adopt the falsifiability method you would have to vehemently disagree as there is no reason to believe it has more than the equivalent of planck's length in decimals(or whatever other theory you wish to adopt), by the falsifiability standards that would knock mathematics out as a legitimate subject.
They also believe weird stuff such as "analytical statements" and conclusions such as the idea that mathematics can tell you nothing about the real world.
I have that quote on my wall
"This is not a publication quality thing, we're just crewing around here" Ben Krasnow
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.
@Thomas Horst I'm no biologist either, I have just heard the blood cell thing and made some probably-innacurate assumptions. Take with a lot of salt i guess
@Henry Byers Most cellular waste that cannot be recycled is filtered out of the bloodstream by the kidneys and leaves the body as urine (or the lungs in the special case of CO2). You're right about dead red blood cells, though. The iron in heme is recycled, and the rest is excrete out in bile to be fermented by bacteria in the gut and partially reabsorbed. What isn't is the brown color you referred to.
@Thomas Horst In fact, not all waste goes through the kidneys, just what's water-soluble (which is most of what's in the bloodstream, to be clear), with the rest being processed by the liver and excreted by the gallbladder.
The most significant single source of non-water-soluble waste in the bloodstream is from hemoglobin. The spleen digests dead/'spent' blood cells, both red and white (including those white blood cells which have consumed dead cells and pathogens), recycles the iron from the hemoglobin locally, and excretes the rest of the waste back into the bloodstream mainly in the form of bilirubin, a yellowish-brown pigment, which the liver then extracts and 'conjugates' (binds with proteins) most of it and oxidizes some into biliverdin (a greenish pigment) and excretes both into bile, along with a number of other things in smaller quantities, including excess fat. Though, the liver doesn't excrete all of what it processes, it also breaks down some insoluble things into soluble components, which are recirculated to the kidneys. Bile of course is secreted into the digestive tract at the duodenum, just behind the stomach, and the useful parts of it are reabsorbed, but the conjugated bilirubin and biliverdin is not, and they form the primary pigmentation in feces.
The pancreas also secretes pancreatic juice into the intestine, and I think there are other minor glands, but as far as I can tell there are no waste products in that, just carbonate and some enzymes.
@yi meizi Seems like that would be way too dependent on body mass to generalize to "per person". "per 100 kg body weight" or "per thousand kcal consumed" would be more useful, as that would take into account varying size of humans and activity levels. Applying something that generic to the exact data form the Soylent project can give a ball park idea, but I wouldn't trust the number exactly. 90% seems high, but still within plausible bounds.
Great process and effort! I suspect that the efficiency would go up as you correct for mass. Id be very surprised if the ingestest dry mass was equal to the excreted dry mass, considering one is essentially shedding cells all the time. Still, I would not expect the overall efficiency to go well beyond like 35%. So the results seem pretty reasonable to me.
Impressive as always. Would be awesome to cost effectively perform a nutritional analysis on the intake, then monitor the metabolism processes with maybe GC/LC and then test the output. Bomb calorimetry is powerful alone too and for some reason thermogravimetric analysis comes to mind... though that's a polymer analysis tangent. Anyway, wondering how a cost effective nutritional analysis can be had. Personally, I think we need to advocate the USDA and/or MDA's and/or public universities provide free sample testing when we bring samples in... or at least minimum required expenses since there are plenty of systems out and about maybe even at the county level.
This was one of the most interesting videos I've seen! It won't help me much in real life but it's still cool to know! Great job through the whole video! I've often wondered how many calories are in flammable liquids, do metals have calories and does water have any calories? I'd love to see something about that! Thank you for your hard work on this video, it was really interesting to watch!
When you used the aluminum block instead of the glass composite window you could swap the silicone o-ring for a copper or aluminum crush washer. That should eliminate any burning problems. You could also cut concentric grooves into the faces of the crush washer to improve its sealing ability, similar to how X-rings work.
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.
@PKMartin We did the peanut in our school. The experiment was titled "how to stink up the classroom without getting in trouble"
@PKMartin ñ poop ñ pop por
No pues
yo is that NightHawkInLight from Metacafe
The excess globs after the burning was the most ingesting thing for me. Really makes you question how much you're actually absorbing, particularly of more synthetic foods
I have to say, you really gave it you're all on this one Ben!
I love how your mind works & leaning from you!👍
It would be interesting to use a second known source of heat (apart from the benzoic acid) to confirm the calibration was working correctly. Really, really awesome stuff! (I think diet and metabolism science folks would be super interested in this setup for rigorous measurements)
I think an interesting follow-up would be to use the same diet on multiple individuals and collect stool samples. Then use the same method to burn each for the caloric content and see if different individuals absorb different amounts of calories from the same sustenance. I feel like that would be an interesting experiment that could provide visual proof in a unique method how everybody processes calories differently.
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 🤣
@Peter the Peter lol
He should try to not eat anything at all for a week or so and measure the "pure" poop. That way at least we could try to work out how much of the food doesn't get digested at all.
@max Well, we lose 40.000 skin cells per minute, so that is about 400m cells we lose in our skin alone, those will cost energy to replace.
@max Your body regenerates almost all of the cells in the body and skin every 2 weeks, so in 1 week, yes A lot.
"The process is basically making astronaut ice cream. It's exactly the same." I no longer like astronaut ice cream.
Loved this stuff and would love to see more of this. The dietary science stuff is so lacking despite it being so important and part of everyone. Has always boggled my mind that we haven't spent more on figuring this stuff out considering it is of importance to literally everyone in some form or another.
Intresting, id like to see more for sure 👍
I've always wondered how they come up with those lable values.
I've always wanted to do calorimetry experiments with my microwave to measure its efficiency. I figure if I get a shallow, glass pan with roughly the same dimensions as my microwave, fill it with a known volume of water, measure the temperature, then run the microwave for a given amount of time, and measure the change in temperature, I can work out how many joules, and taking the time into account, how many watts were imparted into the water and simply take the difference of that figure and how many watts my microwave actually draws, measured with a kill-a-watt meter connected to the microwave and work out just how efficient my microwave is. I'm sure efficiency varies from model to model, and probably depends on how much power the microwave draws, the dimensions, how well built it is to contain the microwaves, and so on. Even something like altitude would probably affect it, as there would be a different amount of air present to absorb some of the microwaves.
There's no real purpose to this experiment, other than curiosity and of course, the fun of exploring science. Plus, I've always wanted to do some sort of calorimetry, but it's difficult without a vacuum chamber. And I got thinking one day, and came up with this idea. So, one of these days I'll do it.
I had to actually do that experiment. My girlfriend's microwave stopped working, and she said it had been getting weaker before that. I fixed the broken plastic fan, calculated how long it ought to take to boil one cup of water based on 600 watts, and temperature change of 90° Celsius, efficiency of 90%, plus some energy for the cup. It boiled right when expected. Only the fan was broken, the oven part worked perfectly, and she was wrong about the oven getting weaker.
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?
@Maximilian I know all about the metabolism of alcohol. As a hobby scientitian and ex-alcoholic I made it my business to know about ADH, ALDH, CYP2E1 and how the body deals with it. At the peak of my addiction I was drinking isopropyl alcohol by the quarter pint, I researched all of this during recovery to find out how much damage I'd done to myself. As it happens the isopropyl, although around 4× more damaging, actually kind of evened out due to the lower dose required to stop the withdrawals. Obviously the top end of my digestive tract disagreed, but it wasn't the threat to my life that the withdrawals were.
And here I thought I was the only one expecting him to lay out a log on the kitchen scales.
Excellent video. Excellent.
@drdca if it ends up in CO2 then the energy has been extracted. That's the amount we want to measure.
@Michael O'Brien poop is clearly more concentrated than food, if you eat a pound of food you dont poop out a pound, unless its 99% fiber.
Exactly, what I am always curious about: labelled Calories vs. digested Calories. I had a hypothesis for years and it wasn't proven until now. I hypothesized that the calories on food labels doesn't determine accurately how much food is being 'burn' in the body efficiently. According to your data, it seems like 25% to 30% efficient. I suspect it varies from individual to individual. That would be an interesting study in the future. Thanks!
Wouldn't we need to eat 3x more or is the bmr already compensated?
Interesting video. It received my full attention. It would also be interesting to see how much energy is unabsorbed for people with their gall bladder removed. Good video Ben.
Wow, this one was great! It was interesting, intriguing, informative and, of course, quite funny >.<
And on a similar vein to the topic of the video, our muscles are around 70% efficient in turning the absorbed energy from food (as atp) into motion, which is way better than something like an ICE. They blow basically any Carnot cycle heat engines out of the water. If your muscles were a kind of heat engine, it essentially as if they worked on a temperature difference of 5000°K.
this reminds me of a question from my days as a runner.. i always assumed i was bruning about 100 kcal per mile. i also found that i lost about 1 pound of weight by dehydration for every 3 miles i ran. i assume that water lost to dehydration means that water had it's temperature raised from normal body temperature to boiling temperature. i never quite did the math, but it seems like it corelates closely with your experiment, where the weight of water lost to dehydration is a measure of total heat produced by normal body metabolism plus the additional heat from burning the calories from running. any thoughts?
Well when you run you lose water by sweating and by respiration. None of the water is "raised to boiling temperature", it just evaporates at your body temperature and removes heat equal to the heat of vaporization. Water vapor that you exhale might have been produced directly from metabolism without ever condensing. Sweat on the other hand evaporates as long as the air isn't at 100% humidity, and as it does so it removes heat from your skin.
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.
@Big Shrimp tbh hvac work can be pretty interesting, especially if you move into conception
@Cape kraken the first guy criticized public school, not schooling in general, you straw manned from the beginning.
"Shut up and burn your peanut" Is a really great example of how schools are teaching kids all wrong.
@Cape kraken You're proof that schooling produces plenty of vegetables already.
@Aggrobiscuit thanks man really made my day, hope you have a good one as well
To qualify this you need to measure the input volume and output volume. Knowing the caloric value of these materials will then allow the calculation of total energy in and out.
First of all, excellent work! You have put lot of effort and heart into it👍 So much for science.
There are few things you might not have thought would end up in the output. 1st is your gut microflora (it is said that every pinch of human output has more number of microflora in it than the entire population of humans living on earth). 2nd is your GIT epithelium being shed. 3rd is the digestive enzymes (which are all proteins) along with bile.
Your calculation and measurements would be at it's best if the output sample was from the tail end day of your regulated diet period.
Would be really interesting to see this done over a longer period of time! and with different foods, people, etc
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.
Disclaimer: please don't eat gas
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
"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.
It's actually a bloody difficult task to laminate clear acrylic, I got pretty good at it but still only got one of every five or so that I was happy with. That was assembling them in a negative pressure glovebox, clamping and then off-gassing and curing in a vacuum. It took a lot of experimenting with the clamp design to get it bubble free without leaving it slightly concave.
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
You're a freaking hero. I'd love to see a video of softwares you use or a tour of the lab and things you can do and order to do from labs and stuff. Kind of a maker showcase
Love this video. I have often wondered if zero calorie sweeteners simple have flame suppressant in them to fool this test. People gain sooooo much weight from ingesting zero calorie drinks, how is that even possible?
Super interesting episode thanks for all your effort.
Would love to see a meat diet VS carbohydrates diet (equal calories) poo burning experiment. (maybe with celery for fibre / to avoid constipation)
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 !
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?
@Het Smiecht Some of it, but CO2 is a waste product of our metabolism.
sauercrowder - 2021-02-27
Thanks, this video convinced me. Finally going to replace my digestive tract with a flame
mikebarnacle - 2021-12-12
Oh. Urine I guess. Urine isn't water... Fair enough, I see. I would like to know how much then practically that can throw off the numbers. I wouldn't suspect it's a significant figure.
manaquri - 2021-12-12
@mikebarnacle afaik most of the mass you lose is through exhaling co2, you take in o2 and add carbon.
On average you loose 200g of carbon per day this way.
You also lose water by perspiration and peeing, and non digestible elements via pooping.
Note this is a simplification, but it's at least 90% like that.
Soylent powder is like 300g per day, so the calculations may be off by a factor of 3.
If that's the case you'd need to compare 150g of Soylent to 50g of poop.
If we plug in the numbers the human digestive system is ~75%±15%* efficient instead of ~25%.
* Taking 250-400g of powder daily intake, because I'm not sure the amount used
Eagle Warrior - 2021-12-14
@manaquri Not to mention that digestive systems vary from species to species vastly. But the human digestive system is actually comparable to vultures. Which is really acidic stomach juices considering vultures can eat corpses that have cyanide.
J B - 2021-12-23
If you replaced it with a flame, calorie listings on packages would finally be meaningful to you
m3sca1 - 2022-04-13
hahahaaa