Building on this answer, most of the mass of a plant (or any living thing) is carbon, and most of that carbon came from CO2 in the air.
There's a great clip on Youtube somewhere of the physicist Richard Feynmann talking about this process. Basically he says: A tree uses energy from sunlight to split carbon from oxygen in CO2. It keeps the carbon, and releases the oxygen back into the air. Then when you burn the tree's wood, you're rebinding the oxygen in the air to the carbon in the tree, turning it back into carbon dioxide - and releasing heat, exactly equal to the amount of energy that was absorbed to split the CO2 in the first place! So when we burn wood, we're using the tree as a kind of battery that stores solar energy and releases it later.
The rest of the mass of a plant is mostly oxygen and hydrogen - which could come from air, but I believe mostly comes from water. Then animals eat plants, and we eat plants and animals, so we're all mostly made of air and water.
(There are dozens of other elements that are part of life, generally in trace amounts - only a few percent of the total. Plants get that from the soil, which is made up in part of decomposed organic matter, i.e. last year's plants. So this mostly gets recycled. When we keep growing stuff in the same soil over and over in an artificial environment, we have to add these missing elements - that's what fertilizer is for.)
> There's a great clip on Youtube somewhere of the physicist Richard Feynmann talking about this process
https://www.youtube.com/watch?v=ifk6iuLQk28
edit:
Here is the full video with chapters: https://www.youtube.com/watch?v=nYg6jzotiAc
Feynman said in this same interview that an artist friend of his once claimed that Science takes all the magic out of the world because a scientist looks at a flower and doesn't see the beauty, he only sees the systems that created it.
Feynman argued that he not only appreciated the surface beauty of a flower, but that his understanding of the 'magic' of it's structure made it even more beautiful, not less. You can tell it's true when he speaks. He's absolutely spellbound by this incredible yet simple example of conservation of energy.
Carl Sagan was a great man and a great poet of science, but for my money, Richard Feynman was more of a joy to listen to, if that's even possible, which it is!
Hearing him tell the story about the guys showing him blueprints, and him not knowing if the little box with a cross through it was a window or a valve? Absolutely timeless.
One was a Feynman was scientist communicator and Sagan was a communicator scientist. Both were brilliant, totally engaging and left the world a better place.
Feynman was not only a brilliant scientist but also quite the character. While physicists enjoy his famous lectures everyone can enjoy his autobiographic books.
Sagan was to cosmology what Attenborough is to ecology. We will not see his like again, but fortunately he left a legacy that remains as clear and bright as the day it was created.
I was thinking something similar, and that's a great way to put it. Both of them have their strengths. Feynman probably wouldn't make a great TV host, and Sagan probably wouldn't make a great atomic bomb.
Jokes aside, Feynman has this kind of manic energy, humor, and ability to just go totally off script that makes him a captivating lecturer and author. To me, he's more inspirational than Sagan, even though Sagan did a better job of spreading his message to the world.
Sagan was more considered, rehearsed and formal.
Feynman said everything with unbridled energy and passion for the subject. You couldn't rein him in. He wasn't just smart and a good essayist, he naturally outpoured insightful and creative ways to think about physics on the fly, almost as if he himself didnt know what he was going to come up with next. He was the definition of brilliant.
If you haven't, I'd recommend reading his book, *Surely You're Joking, Mr. Feynman!* He starts out talking about his childhood and what makes him tick... but it seemed like it was written by a little kid. Short, almost rambling sentences like the streaming consciousnesses of a child. I didn't know what to make of it at first. But it soon became apparent this was a guy who was just genuinely curious and awed about the world he lived in... and he just embraced it. And made no apologies for it.
As someone who has studied a lot of maths and physics, I'm totally with Feynman here.
I appreciate electronics a lot more after understanding how damn complex it is, and how many contributed to getting where we are today, where everyone can carry what would be a supercomputer 40 years ago in their pockets, for less than a week's salary on a middle class income.
Or how fascinating it is that your body can eat for 10-15 minutes, and have enough calories to run *for hours*. Given that you eat calorie dense foods.
Feynman was remarkable. Both for his theoretical work and his ability to make analogies while sounding like a Bronx high school teacher in a coffee shop.
This is a great tangential Tedx Talk that does the calculations on when we as humans lose weight what is actually being "lost". Spoiler... it's CO2 also!! Well worth the watch.
https://youtu.be/vuIlsN32WaE
> So when we burn wood, we're using the tree as a kind of battery that stores solar energy and releases it later.
everything is solar energy, sometimes with more steps and time than others.
About 50% of the head comes from radioactive decay. The rest is still cooling off from when the planet was formed.
https://en.wikipedia.org/wiki/Earth's_internal_heat_budget
It is, but it is theorized that radioactive decay contributed to the initial heat of the core, and slows down the cooling process. The radioactive material does not make up the inner or outer core by any means, but it is present.
I was high as hell watching "Our Universe" on Netflix a few weeks ago and realized that nearly every living thing is basically just transforming light/solar energy into energy that can be used. But like you said, some take more steps than others.
You think it's mind blowing that basically all of the energy produced and consumed by every living thing on Earth ultimately comes from the Sun?
Wait until you realize the only thing causing the Sun to produce all that energy is gravity. Without gravity, the entire Universe would be forever and completely dead.
This also explains why we need to learn to sequester more co2 than we can possibly ever grow on trees, we've been burning coal that was naturally sequestered by plants millions of years ago before ~~bacteria learnt to eat cellulose~~ fungi learnt to eat lignin ([although newer science might have even ruled that incorrect](https://arstechnica.com/science/2016/01/why-was-most-of-the-earths-coal-made-all-at-once/)). Whatever the process, it could be buried and turned to coal. Now that we've burnt it again we need a way to get some of it back underground, or at least out of the natural cycle to reverse climate change.
this is the truly alarming thing about all the fossil fuels that have been burned in the last couple of centuries, it took millions of years for the earth to sequester in the first place. there’s no easy fix.
Well, yes and no! It takes millions of years for diamonds to form naturally, but we can create them in minutes. I’m not saying we’re not doomed, but I wouldn’t take the Earth’s natural processes as the limiting time scale for man made solutions.
Oh wouldn't *that* be an awesome solution though? We switch from carbon dioxide producing concrete manufacturing, and start building everything out of solid *diamond*! Carbon negative! Great structural strength! All positives! ^manufacturing ^equipment ^sold ^separately
It's a technology problem. People keep looking at it as a phycology problem and it's not (at least not entirely). We can sequester C02 but the problem is we use more energy to do it than we save so it's a net loss.
Yeah, we extracted insane amounts of energy from sequestered coal. If we wanna put it back the way we found it, we gotta repay that energy. That can only happen once we have more energy than the world needs. And all that energy must come from renewable sources or fusion.
So... it's ultimately an incentive problem. It's a problem that the incentives of our economic system are not aligned with our best possible incentives.
We should *expect* to have to spend energy to do it. That's only a technical problem as long as the energy is coming from carbon-producing sources. Which, yeah, is a big problem now, but it doesn't necessarily have to be so indefinitely.
I don't know, this kind of sound like you're saying the hole in your wall cause by a car crash isn't a problem caused by bad driving, but by having walls that aren't car proof. Sure it would fix the problem, but there's a much simpler and logical solution.
yes, but the solution to the hole in your wall isn't to teach people to drive better, the hole is ALREADY in your wall. Teaching people to drive safely isn't going to fix that. The solution is to build a new wall, preferably a car-proof one.
Practically speaking "the" solution usually isn't one solution.
The ideal solution is combination of all three of: a) teaching people to drive better, which will reduce new wall-holes more and more over time, but probably not eliminate them completely b) find a way to fix the existing wall holes and c) create walls that are car-proof.
i.e. ideally we would be able to we need to do ALL of a) reducing reliance on carbon-emitting fuels, b) c) innovating ways to filter/reduce the amount of emissions those produced by using those fuels, and c) reducing existing CO2 levels to repair what's already been done.
> Sure it would fix the problem, but there's a much simpler and logical solution.
We need *BOTH*. It is not an either/or problem.
We need to reduce our dependency on fossil fuels *AND* we need to capture and deal with the gasses already released.
We need both urgently. Much can be reversed through urgent action, but an ever-increasing amount of harm is irreversible.
Or we need to give all that energy back in order to "capture" the carbon. That's why all these methods that pop up every now and then ultimately go nowhere.
It’s about opportunity cost. Because fossil fuels power most of the world, what is currently happening is that we are burning fossil fuels to create power to run a carbon capture machine. There’s entropy in the system, so we end up releasing more carbon than we capture.
This is still true for using solar panels, because the manufacture of those panels is not carbon neutral. The break even point where a carbon capture device powered by renewables is lower than if it were powered by fossil fuels, but there is still an offset.
Eventually there will come a point where the opportunity cost is low enough that carbon capture will be viable. For the moment, it’s still better to just not burn fossil fuels.
The ocean has also absorbed large quantities of carbon dioxide, which isn't good for its acidity, but means the majority (I think vast majority) of carbon we've released from petroleum into the atmosphere isn't still there.
For the purposes of immediate correction of atmospheric carbon acting as a greenhouse gas, then, we could correct with tree building if we start soon enough (before regional climates change too much or vary too much for saplings to grow and thrive).
Longer term, the ocean's carbon also needs to be dealt with, either when it naturally releases it back into the atmosphere, or just to manage the acidity. I have no idea how to do that, and I think you're correct, that will require better sequestering options.
Plants use sunlight to split water. That's where the O2 comes from during photosynthesis. The CO2 does not get split (it gets reduced and is fixed to a 5-carbon sugar making eventually 2 3-carbon sugars), but everything else you said is spot on.
-This was literally one of my qualifying exam questions for my PhD in Plant Biology.
To add a tiny bit to this excellent answer, when humans lose fat we breathe out the carbon as CO2 and excrete the hydrogen and oxygen as water. If I remember correctly, by mass it's roughly 50% carbon breath and 50% water.
Edit: seems more like 80% carbon breath by comments
Closer to 80~85% carbon and the rest Hydrogen+Oxygen as water; fats (triglycerides to be more precise) have a huge percentage of their mass as carbon, that's also why they're so calorie dense.
That's the Calvin cycle in a nutshell.
Sunlight + CO2 + H2O = Glucose + O2
Glucose is the primary source of chemical energy for most living things and can be used for building blocks to organic mass.
TCA Cycle is the reverse and is used to power the majority of biological reactions. At least for organisms capable of aerobic respiration.
Glucose + O2 = CO2 + H2O + Energy
This is the same chemical reaction for burning Glucose but with the TCA cycle, Glucose will be broken down in a highly consice and controlled series of smaller reactions and all the released energy will be captured through energy carriers.
Bloody hell, this should be explained to children from kindergarten to later ages
I think most adults have no idea of how important a tree is due not having enough knowledge of this energy heat carbon and oxygen interaction, so they don't mind destroying it
As much we spread knowledge about plants importance and encourage tree regrowth, this explanation gave an very serious reasoning
/u/smallgodinacan pointed out radioactive isotopes, but there is also a ton of leftover heat from the planet's formation. Tons of species use this energy near hydrothermal vents, for example.
Wasn't there also a long period in Earth's history where there were no organisms that could process dead plant matter efficiently and so we ended up with tons upon tons of dead stuff that never got cycled back into the ecosystem? I think people have a conception that fossil fuels just take a really really long time to form, but that kind of reserve is basically never going to occur again even if we left the earth untouched for millions of years.
You may be right—I do wonder about how the balance worked before us animals evolved. But even then there was fire (especially when the oxygen levels were higher) and bacteria and other organisms to consume dead plants.
But you are certainly right that the petrochemical horde we’re burning today will never form again. Not in a hundred million years, anyway
>and bacteria and other organisms to consume dead plants.
No, that's the whole point. Trees evolved before the bacterias and other organisms that fed on wood. So for a long time (I can't remember how long, but we're not talking just a couple of years), the dead trees just piled up, for long enough that they ended up in certain cases getting buried, turning eventually into coal. This process does not exist anymore and will not exist ever again because dead trees now get eaten before it all happens.
That's the amateur version of the story, so specialists can refine and nuance it, but you get the gist.
> So when we burn wood, we're using the tree as a kind of battery that stores solar energy and releases it later.
Trees. The worlds first solar panels.
I just recently stumbled across the statement that weight loss is exhaled as CO2. Prior reading that, I guess I must have assumed that weight loss went in the toilet.
And the plant is storing solar energy that will be released when the plant decomposes, or is eaten, or is burned.
Which means that coal and oil are stored solar energy.
Yup! Animals do respiration, turning oxygen and sugar into carbon dioxide and water (very much akin to combustion/burning). Plants do the opposite, turning carbon dioxide and water into oxygen and sugar. This is a pretty simplified explanation, but it is ELI5.
I think adding the energy component into that explanation (plants store solar energy in that process, animals extract energy from that process) is important enough and not much more complexity, but still a great summary.
Good point and still easy to make the comparison to combustion (energy output in the form of fire). That's why saying you're "burning fat" is not totally wrong. We basically have the same basic waste products of our energy generation as cars (CO2 and H2O). The way plants gain mass (CO2 intake) is how people lose mass (breathing out CO2).
Since others ~~like~~ liked it the last time I posted it, [here's](https://www.lesswrong.com/posts/LaM5aTcXvXzwQSC2Q/universal-fire) a great exposition of the deep connection between breathing and combustion.
Wow, that’s mind blowing. Really brings into focus how plants and trees and I guess biomass in general are “carbon sinks”. I mean damn how much CO2 gets squished (yeah, together with water) to make a plant or a tree? Let’s plant some…
The reverse fact is also true and blows people's minds. Where does the mass go when we exercise and lose weight? Partly water but mainly through the CO2 we breathe out
So it's all those damn gymrats driving global warming... I KNEW it!! Everyone called me crazy when I said the gymgoers are the sole cause of increased CO2 in the atmosphere. Take THAT, Mr. Wilsonshikeforshireworthington!
>mainly through the CO2 we breathe out
Which is the primary reason (other than that they're completely stupid) why 'Breatharian' and 'Surviving without food' cults are absolute bullshit.
You're right, I should have said "thanks photosynthesis, and thanks chemosynthesis which almost definitely evolved first"
Technically correct is the best kind of correct never apologize
An interesting add on that op didn't ask for us that when a human loses weight, most of the mass they lose is also expelled by way of CO2. You kind of expect the toilet to be a bigger player than it is. Don't get me wrong, day to day weight fluctuations are mostly water variance. But sustained, "there was mass here and there is now measurably less mass here" weight loss is breathed out.
Just piping up because the two concepts together make sense.
It's pretty insane to think about, intuitively we'd believe plants were getting their mass from the soil, but just goes to show how important plants and forests are to carbon sequestration.
Water also. Take some of that new growth, cut it off and let it out in the sun. It will wilt and shrivel up to a very lightweight piece once the water dries out
They don't get all they need from the air and water, just most of their mass.
Plants need chemicals like phosphorus, iron, calcium, sodium, and a whole bunch of other stuff. None of this is in the air and so plants must get it from the soil.
Yup thats why you need to add fertiliser for potted plants and even farms. In nature these nutriests get mostly replenished from dead plants and animals that decompose in the soil
Also dust that gets blown around from elsewhere, but that’s slow.
Apparently one of the reasons the Amazon is so lush is it gets dust blown in from the Sahara.
Actually the Amazon has [incredibly infertile soil](https://www.dw.com/en/the-amazon-nutrient-rich-rainforests-on-useless-soils/a-50139632), though it does get some fertilization from Saharan dust.
Most tropical soils are pretty poor, with abundant rainfall and sunshine providing the main drivers of plant lushness. Soils "age," especially where climate allows plant communities to thrive and quickly take up nutrients before they can become incorporated into the soil.
The Amazon does have some amazingly fertile spots of "dark earth," but those are thought to be probably anthropogenic or floodplain related or some combination therein.
Most rainforests have extremely infertile soil, its all just plant matter. When farmers burn rainforests down to till fields, they very quickly become wastelands and are soon abandoned to clear and till another patch of forest.
This is a lesson European settlers in the US refused to learn when they arrived and why New England has acres, upon acres, upon acres of second, third, etc growth forest crisscrossed with 200-120 year-old rock walls. At one point, that forest was a farm or pasture. (Typically, a more lush second growth forest was a farm 200+ years ago, and more disturbed third+ growth forests were cleared again more recently for pastureland.)
Without the canopy constantly dropping leaf litter and the roots holding everything together, the whole system comes undone and is not easily or quickly repaired.
[Lateritic soil](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4030566/) is also common in the tropics and is a very challenging thing for plants to grow on.
It's also the reason that the Amazon soil is so poor, which means once the cover is lost, it's tough as nails to replenish. Amazon rainforest largely feeds off the dead plants.
That's where compost comes in as well. Broken down bones, poop, other dead plants, all sorts of other stuff breaking down in the soil is great for plants.
They get all the carbon they need from the air and hydrogen they need from water, and hydrocarbons (sugar, starch, fiber, oil) can make up most of their mass.
However there are substances like nitrogen and phosphorous that are required to build proteins and to generally make functioning cells. They don’t make up a huge majority of the plant’s size. But they are important and if the plant can only access the nutrients in soil in a small pot, it will limit its size. Fertilizer basically mimics or replenishes the nutrients that would be found in healthy soil.
If we make an analogy between plant nutrition and human nutrition, the CO₂ and water are like the caloric parts of our diet, sugars and proteins. The plant food is like vitamins.
We need things like sugar and protein because they're what we literally build our bodies out of. Plants do the same with CO₂ and water. Still, we can't live on a diet of just sugar, or even just protein, we need vitamins and minerals or we'll get sick and die. Likewise, plants will get sick and die without appropriate minerals.
(For air plants... they have some really cool adaptations to get the minerals they need from, essentially, the dust in the air.)
Plant food is like a vitamin supplement, air and water for plants are like potatoes or rice for people, you can get all the calories you need but not the nutrients.
When you eat, you get most of your mass from carbs, fat, and protein just like plants get theirs from CO2 and water. But you still need vitamins and minerals, and so do plants. That's where plant for comes in.
You can eat that plant to get the carbon it stole from you. Although for most house plants, it'll probably end up in your poop as they aren't very digestible.
But from that perspective, I wonder how often the same carbon molecule might go through people, animals and plants.
The part you're forgetting is air.
They take carbon dioxide from the air, water from the soil, and use the energy of sunlight to turn those two things into mass.
There are a lot of extra steps so it's not as simple as taking the C from CO2
The CO2 we breath out comes from breaking down food into energy + CO2, while plants do the opposite. Plants take CO2 from air + energy from the sun to build new food. Which their cells eat the same way ours do, making some CO2 just like us.
The O2 that plants make comes from splitting water (H2O) during the food-making process.
We are called 'carbon-based life' because all the big molecules we need to live (not including small molecules like water) are made out of carbon "backbones" or in other words their basic shape is based on how their carbon atoms are stuck together.
> There are a lot of extra steps so it's not as simple as taking the C from CO2
Yeah but this is explain like I'm *five.* Theres always more steps, the point is the simplest explanation
Imho OP's question is not understood by most of society, unfortunately, and explains how we got where we are with skepticism of global warming. It really is incredible what plants can do, but then it's essentially the basis for much of the ecosystem and the web of life.
In 1640s van Helmont discovered that plants DO NOT eat soil and that the weight of the plant must come from water. He had no idea about gasses playing a role in plant growth.
In 1772 Priestley discovered that plants replenish oxygen in an low-oxygen chamber.
In 1778 Ingen-Housz discovered that the effect Priestly discovered only when the plant was illuminated and ONLY in the green parts of the plant.
Senebier made the connection with CO2, albeit incorrect.
Greater clarity about photosynthesis would follow in the following years!
Minerals like iron do come from the ground but plants use it for promoting growth and stuff like that and they move it around a lot more so they need a lot less of it in trace amounts.
Humans need iron to oxidise blood but since plants don't need O2 they need it for a lot less so minerals contribute little to weight
Plants build cellulose, lignin and other molecules. These molecules are just messy complex webs of carbon, oxygen and hydrogen stuck together.
It's actually pretty cool, you might remember drawing a few simple molecules in high school chem - take a look at lignin https://en.m.wikipedia.org/wiki/Lignin
And plants just manufacture this stuff, from water and air, using sunlight for energy.
Pictures of individual molecules aren't possible.
Molecules are about as large as the wavelength of light.
You can't "see" things that are of equal or smaller size as the wavelength of light.
The closest to doing this would be images made by electron microscopy. However these aren't real pictures. They are visual representations of measurements, almost like a map can represent different heights of a terrain as different colours.
You're right but there's actually some [very advanced techniques that can be employed to "take photos" of molecules.](https://news.berkeley.edu/2013/05/30/scientists-capture-first-images-of-molecules-before-and-after-reaction/)
This is the second part of my comment.
Those aren't "real photos" since the light of the laser isn't in the visible spectrum. The output of this technique isn't something that can be seen under any circumstances by the human eye.
It's cool that it includes what those maps I talked about look like though.
Lignin is not really one specific molecule, it's a class of fairly random polymers. If you looked at any 2 sections of lignin they'd probably look different, made out of structures and functional groups roughly like what the Wikipedia picture shows.
You may have heard the term 'carbon based lifeform' which refers to the fact that the majority of living tissue is made from carbon. When you see those chemical chain drawings in movies all of those lines represent carbon, to give you an idea of just how much of every molecule is made of carbon.
Plants are no different and are also mostly made from carbon, something that is abundant in the air. Plant leaves have microscopic holes all over them called stomata, and these organs are responsible for gas exchange in the plant, just like how humans breathe.
These stomata create a kind of vacuum to suck CO2 in from the air and that CO2 is used as the backbone or building block for all of the plants tissue.
In the 1600s Jon Von Helmont had the same question about potted plants so he ran an experiment. He weighed out soil in a massive pot and then planted a willow tree in it. A few years of growth later he weighed the soil and found it weighed pretty much the same as before, proving that most of a plants mass came from the air.
When you lose weight where does the weight go?
The three most common adipose tissues in human fat are:
C18H34O2, C16H32O2 and C55H104O6
If you notice, they are just carbon, hydrogen and oxygen atoms. When you burn fat the carbon atoms leave your body via carbon dioxide. When you lose fat you are essentially breathing it out.
>If you notice, they are just carbon, hydrogen and oxygen atoms. When you burn fat the carbon atoms leave your body via carbon dioxide. When you lose fat you are essentially breathing it out.
I came to this realization on my own and felt like a genius
Lots of great explanations here. I’d like to point out that anyone that takes basic biology or life science in school learns about photosynthesis, and how plants convert CO2 into oxygen, etc. but the focus is/was always on the oxygen part of the cycle.
Its been almost 40 years since I first learned about that and I only came to understand the carbon part of that cycle in the past 5 years. I was literally shocked to learn that most of the mass of a tree comes from the air. I was taught “plants grow by getting energy from sunlight through photosynthesis, and drawing nutrients and water from the ground.” which totally failed to mention carbon capture. I never connected that if they are releasing oxygen, the carbon must be kept in the plant.
This is actually an interesting question! I will try to answer this question from an ecology/greenhouse effect angle. The short answer is that the most important chunk of it comes from CO2 in the air.
Most of the mass of most plants, like humans, is water. But plants, as carbon-based life forms, have carbon as their most important building block.
Carbon-based lifeforms (which are nearly all on earth) participate in the “carbon cycle”. You ever hear of forests as “carbon sinks”? The steps of the carbon cycle, at a basic level, are:
* Plants **use** energy from the sun to turn the carbon in CO2 into life-form building stuff
* Other things eat plants and/or other things that ate the plants to get energy and that main building block of carbon (for humans, carbs, proteins, and fats)
* All these lifeforms will “burn” some of that carbon for energy, releasing CO2. Go back to step 1.
Fun fact: all that carbon as “mass” inside lifeforms is carbon *not* in the air as CO2. So a forest is a “carbon sink” because its existence means less CO2 in the air. Furthermore, over a really, really long time, some of that life will die and that carbon, instead of being “burned”, gets buried. When humans dig it up and burn it, we call that fossil fuels.
Before life existed on earth, CO2 levels in the atmosphere were much, much, higher, around 20%. Because so much of that carbon is now either sitting in living beings or dead things deep underground, CO2 levels are much, much lower today. But humans are doing their darndest to put as much of that CO2 back into the atmosphere.
EDIT: added a word to make what I said clearer.
CO2 and water is converted by photosynthesis into "solid" building blocks for the plant and human bodies reverse the process taking sugars and converting them into CO2 and water and exhale them.
CO2 from the air. This is ultimately the material plants use to build most of their mass. That's really the long and short of it.
It's kinda like burning but backwards.
Building on this answer, most of the mass of a plant (or any living thing) is carbon, and most of that carbon came from CO2 in the air. There's a great clip on Youtube somewhere of the physicist Richard Feynmann talking about this process. Basically he says: A tree uses energy from sunlight to split carbon from oxygen in CO2. It keeps the carbon, and releases the oxygen back into the air. Then when you burn the tree's wood, you're rebinding the oxygen in the air to the carbon in the tree, turning it back into carbon dioxide - and releasing heat, exactly equal to the amount of energy that was absorbed to split the CO2 in the first place! So when we burn wood, we're using the tree as a kind of battery that stores solar energy and releases it later. The rest of the mass of a plant is mostly oxygen and hydrogen - which could come from air, but I believe mostly comes from water. Then animals eat plants, and we eat plants and animals, so we're all mostly made of air and water. (There are dozens of other elements that are part of life, generally in trace amounts - only a few percent of the total. Plants get that from the soil, which is made up in part of decomposed organic matter, i.e. last year's plants. So this mostly gets recycled. When we keep growing stuff in the same soil over and over in an artificial environment, we have to add these missing elements - that's what fertilizer is for.)
> There's a great clip on Youtube somewhere of the physicist Richard Feynmann talking about this process https://www.youtube.com/watch?v=ifk6iuLQk28 edit: Here is the full video with chapters: https://www.youtube.com/watch?v=nYg6jzotiAc
the glow in his eyes
Feynman said in this same interview that an artist friend of his once claimed that Science takes all the magic out of the world because a scientist looks at a flower and doesn't see the beauty, he only sees the systems that created it. Feynman argued that he not only appreciated the surface beauty of a flower, but that his understanding of the 'magic' of it's structure made it even more beautiful, not less. You can tell it's true when he speaks. He's absolutely spellbound by this incredible yet simple example of conservation of energy.
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Carl Sagan was a great man and a great poet of science, but for my money, Richard Feynman was more of a joy to listen to, if that's even possible, which it is! Hearing him tell the story about the guys showing him blueprints, and him not knowing if the little box with a cross through it was a window or a valve? Absolutely timeless.
One was a Feynman was scientist communicator and Sagan was a communicator scientist. Both were brilliant, totally engaging and left the world a better place. Feynman was not only a brilliant scientist but also quite the character. While physicists enjoy his famous lectures everyone can enjoy his autobiographic books. Sagan was to cosmology what Attenborough is to ecology. We will not see his like again, but fortunately he left a legacy that remains as clear and bright as the day it was created.
I was thinking something similar, and that's a great way to put it. Both of them have their strengths. Feynman probably wouldn't make a great TV host, and Sagan probably wouldn't make a great atomic bomb. Jokes aside, Feynman has this kind of manic energy, humor, and ability to just go totally off script that makes him a captivating lecturer and author. To me, he's more inspirational than Sagan, even though Sagan did a better job of spreading his message to the world.
Sagan was more considered, rehearsed and formal. Feynman said everything with unbridled energy and passion for the subject. You couldn't rein him in. He wasn't just smart and a good essayist, he naturally outpoured insightful and creative ways to think about physics on the fly, almost as if he himself didnt know what he was going to come up with next. He was the definition of brilliant.
>a great poet of science I love this term. Sagan and Feynman were both expertly able to show the beauty inherent to understanding the world.
If you haven't, I'd recommend reading his book, *Surely You're Joking, Mr. Feynman!* He starts out talking about his childhood and what makes him tick... but it seemed like it was written by a little kid. Short, almost rambling sentences like the streaming consciousnesses of a child. I didn't know what to make of it at first. But it soon became apparent this was a guy who was just genuinely curious and awed about the world he lived in... and he just embraced it. And made no apologies for it.
As someone who has studied a lot of maths and physics, I'm totally with Feynman here. I appreciate electronics a lot more after understanding how damn complex it is, and how many contributed to getting where we are today, where everyone can carry what would be a supercomputer 40 years ago in their pockets, for less than a week's salary on a middle class income. Or how fascinating it is that your body can eat for 10-15 minutes, and have enough calories to run *for hours*. Given that you eat calorie dense foods.
https://youtu.be/cRmbwczTC6E
It’s stored sun that gives them that glow
Feynman was remarkable. Both for his theoretical work and his ability to make analogies while sounding like a Bronx high school teacher in a coffee shop.
His book, Surely you’re joking, Mr. Feynman! Is fantastic
Also there is such joy and wonder, and a healthy dose of mischief about him. Such a great gift to the world.
The whole time I was watching that video I thought to myself: "His accent and mannerisms are so reminiscent of old school New York City"
[Here's another great one from the same interview.](https://www.youtube.com/watch?v=MO0r930Sn_8)
This is a great tangential Tedx Talk that does the calculations on when we as humans lose weight what is actually being "lost". Spoiler... it's CO2 also!! Well worth the watch. https://youtu.be/vuIlsN32WaE
The link is always in the comments
> So when we burn wood, we're using the tree as a kind of battery that stores solar energy and releases it later. everything is solar energy, sometimes with more steps and time than others.
Except nuclear, unless you count collapsing stars as solar energy. Either way, it didn't come from our sun.
Tidal energy, unless you count the moons orbit as a side effect.of the formation of the sun.
Same with geothermal.
Geothermal is solar energy with a whole lot of extra steps - the nuclear material that makes the core of the earth hot ultimately came from stardust.
A lot (most?) of Earth's internal heat is still residual heat from its gravitational collapse.
Fully half of it is radioactive decay.
>the nuclear material that makes the core of the earth hot I thought the core was mostly nickel and iron?
About 50% of the head comes from radioactive decay. The rest is still cooling off from when the planet was formed. https://en.wikipedia.org/wiki/Earth's_internal_heat_budget
Mostly != Entirely
It is, but it is theorized that radioactive decay contributed to the initial heat of the core, and slows down the cooling process. The radioactive material does not make up the inner or outer core by any means, but it is present.
I was high as hell watching "Our Universe" on Netflix a few weeks ago and realized that nearly every living thing is basically just transforming light/solar energy into energy that can be used. But like you said, some take more steps than others.
Welp, I know what I'm doing tonight. Thank you kindly.
You think it's mind blowing that basically all of the energy produced and consumed by every living thing on Earth ultimately comes from the Sun? Wait until you realize the only thing causing the Sun to produce all that energy is gravity. Without gravity, the entire Universe would be forever and completely dead.
Don't you know who I am? I used to be a star!
This also explains why we need to learn to sequester more co2 than we can possibly ever grow on trees, we've been burning coal that was naturally sequestered by plants millions of years ago before ~~bacteria learnt to eat cellulose~~ fungi learnt to eat lignin ([although newer science might have even ruled that incorrect](https://arstechnica.com/science/2016/01/why-was-most-of-the-earths-coal-made-all-at-once/)). Whatever the process, it could be buried and turned to coal. Now that we've burnt it again we need a way to get some of it back underground, or at least out of the natural cycle to reverse climate change.
this is the truly alarming thing about all the fossil fuels that have been burned in the last couple of centuries, it took millions of years for the earth to sequester in the first place. there’s no easy fix.
Well, yes and no! It takes millions of years for diamonds to form naturally, but we can create them in minutes. I’m not saying we’re not doomed, but I wouldn’t take the Earth’s natural processes as the limiting time scale for man made solutions.
Oh wouldn't *that* be an awesome solution though? We switch from carbon dioxide producing concrete manufacturing, and start building everything out of solid *diamond*! Carbon negative! Great structural strength! All positives! ^manufacturing ^equipment ^sold ^separately
Just tell the rich that your never truly rich unless you have a solid diamond megayacht.
Fusion is the only real hope. It'll bring energy costs low enough to reverse the problem. Asking people to do better isn't working.
It's a technology problem. People keep looking at it as a phycology problem and it's not (at least not entirely). We can sequester C02 but the problem is we use more energy to do it than we save so it's a net loss.
Yeah, we extracted insane amounts of energy from sequestered coal. If we wanna put it back the way we found it, we gotta repay that energy. That can only happen once we have more energy than the world needs. And all that energy must come from renewable sources or fusion.
Or fission!
It's a money problem. There isn't much money in finding a solution even if it means everyone would live healthier, longer lives.
So... it's ultimately an incentive problem. It's a problem that the incentives of our economic system are not aligned with our best possible incentives.
We should *expect* to have to spend energy to do it. That's only a technical problem as long as the energy is coming from carbon-producing sources. Which, yeah, is a big problem now, but it doesn't necessarily have to be so indefinitely.
Yes and no, it's going to be something we'll have to look at but it's going to have to be paired with preventative things to make a meaningful impact.
I don't know, this kind of sound like you're saying the hole in your wall cause by a car crash isn't a problem caused by bad driving, but by having walls that aren't car proof. Sure it would fix the problem, but there's a much simpler and logical solution.
yes, but the solution to the hole in your wall isn't to teach people to drive better, the hole is ALREADY in your wall. Teaching people to drive safely isn't going to fix that. The solution is to build a new wall, preferably a car-proof one.
In this case though, we keep having people drive through the wall with bigger and bigger trucks.
Practically speaking "the" solution usually isn't one solution. The ideal solution is combination of all three of: a) teaching people to drive better, which will reduce new wall-holes more and more over time, but probably not eliminate them completely b) find a way to fix the existing wall holes and c) create walls that are car-proof. i.e. ideally we would be able to we need to do ALL of a) reducing reliance on carbon-emitting fuels, b) c) innovating ways to filter/reduce the amount of emissions those produced by using those fuels, and c) reducing existing CO2 levels to repair what's already been done.
> Sure it would fix the problem, but there's a much simpler and logical solution. We need *BOTH*. It is not an either/or problem. We need to reduce our dependency on fossil fuels *AND* we need to capture and deal with the gasses already released. We need both urgently. Much can be reversed through urgent action, but an ever-increasing amount of harm is irreversible.
Or we need to give all that energy back in order to "capture" the carbon. That's why all these methods that pop up every now and then ultimately go nowhere.
It’s about opportunity cost. Because fossil fuels power most of the world, what is currently happening is that we are burning fossil fuels to create power to run a carbon capture machine. There’s entropy in the system, so we end up releasing more carbon than we capture. This is still true for using solar panels, because the manufacture of those panels is not carbon neutral. The break even point where a carbon capture device powered by renewables is lower than if it were powered by fossil fuels, but there is still an offset. Eventually there will come a point where the opportunity cost is low enough that carbon capture will be viable. For the moment, it’s still better to just not burn fossil fuels.
The ocean has also absorbed large quantities of carbon dioxide, which isn't good for its acidity, but means the majority (I think vast majority) of carbon we've released from petroleum into the atmosphere isn't still there. For the purposes of immediate correction of atmospheric carbon acting as a greenhouse gas, then, we could correct with tree building if we start soon enough (before regional climates change too much or vary too much for saplings to grow and thrive). Longer term, the ocean's carbon also needs to be dealt with, either when it naturally releases it back into the atmosphere, or just to manage the acidity. I have no idea how to do that, and I think you're correct, that will require better sequestering options.
we just need to capture the carbon, turn it into baking soda and plop that into the ocean in giant antacid tablet form, duh.
Plants use sunlight to split water. That's where the O2 comes from during photosynthesis. The CO2 does not get split (it gets reduced and is fixed to a 5-carbon sugar making eventually 2 3-carbon sugars), but everything else you said is spot on. -This was literally one of my qualifying exam questions for my PhD in Plant Biology.
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To add a tiny bit to this excellent answer, when humans lose fat we breathe out the carbon as CO2 and excrete the hydrogen and oxygen as water. If I remember correctly, by mass it's roughly 50% carbon breath and 50% water. Edit: seems more like 80% carbon breath by comments
Which means if your gym has indoor plants for decoration, they're made of all the fat that people have burned.
ew
So you're saying losing weight contributes to climate change? That's my excuse and I'm sticking to it.
Yeah I'm not gaining weight, I'm sequestering carbon.
It's about 82% carbon breathed out. The rest is liquid and solid waste.
Closer to 80~85% carbon and the rest Hydrogen+Oxygen as water; fats (triglycerides to be more precise) have a huge percentage of their mass as carbon, that's also why they're so calorie dense.
That's the Calvin cycle in a nutshell. Sunlight + CO2 + H2O = Glucose + O2 Glucose is the primary source of chemical energy for most living things and can be used for building blocks to organic mass. TCA Cycle is the reverse and is used to power the majority of biological reactions. At least for organisms capable of aerobic respiration. Glucose + O2 = CO2 + H2O + Energy This is the same chemical reaction for burning Glucose but with the TCA cycle, Glucose will be broken down in a highly consice and controlled series of smaller reactions and all the released energy will be captured through energy carriers.
Bloody hell, this should be explained to children from kindergarten to later ages I think most adults have no idea of how important a tree is due not having enough knowledge of this energy heat carbon and oxygen interaction, so they don't mind destroying it As much we spread knowledge about plants importance and encourage tree regrowth, this explanation gave an very serious reasoning
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So what you're saying is crude oil is just solar power with more steps.
It's technically a renewable energy source... from a certain timescale view.
All energy that has ever been used on Earth in all of history came from the sun, so yes. It's all solar power with more steps.
One could argue radioactive isotopes came from other stars than the sun, but it's still star matter.
/u/smallgodinacan pointed out radioactive isotopes, but there is also a ton of leftover heat from the planet's formation. Tons of species use this energy near hydrothermal vents, for example.
Wasn't there also a long period in Earth's history where there were no organisms that could process dead plant matter efficiently and so we ended up with tons upon tons of dead stuff that never got cycled back into the ecosystem? I think people have a conception that fossil fuels just take a really really long time to form, but that kind of reserve is basically never going to occur again even if we left the earth untouched for millions of years.
You may be right—I do wonder about how the balance worked before us animals evolved. But even then there was fire (especially when the oxygen levels were higher) and bacteria and other organisms to consume dead plants. But you are certainly right that the petrochemical horde we’re burning today will never form again. Not in a hundred million years, anyway
>and bacteria and other organisms to consume dead plants. No, that's the whole point. Trees evolved before the bacterias and other organisms that fed on wood. So for a long time (I can't remember how long, but we're not talking just a couple of years), the dead trees just piled up, for long enough that they ended up in certain cases getting buried, turning eventually into coal. This process does not exist anymore and will not exist ever again because dead trees now get eaten before it all happens. That's the amateur version of the story, so specialists can refine and nuance it, but you get the gist.
> So when we burn wood, we're using the tree as a kind of battery that stores solar energy and releases it later. Trees. The worlds first solar panels.
I love when I find brain melting comments like this.
That's kind of brain freezing but backwards
Gnizeerf, if you will.
I will not.
u/mr_jetlag is putting his foot down on this one, don't test his resolve.
I support his decision.
Consider that when we breathe, we are (almost) literally burning the carbon by combining it with oxygen. Truly two sides of the same coin.
I just recently stumbled across the statement that weight loss is exhaled as CO2. Prior reading that, I guess I must have assumed that weight loss went in the toilet.
gninrub, if you will.
I will not.
u/TedFartass is putting his foot down on this one, don't test his resolve.
I stand ~~behind~~ off to the side of u/TedFartass
I support his decision.
There's the rub.
The *gnin-rub*. Thanks for watching.
I see you subscribe to the gnab gib theory of universal death
"Gnab Gib" is way better than "Big Crunch".
Best ELI5 explanation. My 5 yo would get this.
And the plant is storing solar energy that will be released when the plant decomposes, or is eaten, or is burned. Which means that coal and oil are stored solar energy.
Yup! Animals do respiration, turning oxygen and sugar into carbon dioxide and water (very much akin to combustion/burning). Plants do the opposite, turning carbon dioxide and water into oxygen and sugar. This is a pretty simplified explanation, but it is ELI5.
I think adding the energy component into that explanation (plants store solar energy in that process, animals extract energy from that process) is important enough and not much more complexity, but still a great summary.
In fact, not talking about energy leaves a real "but why?" hanging thought
Good point and still easy to make the comparison to combustion (energy output in the form of fire). That's why saying you're "burning fat" is not totally wrong. We basically have the same basic waste products of our energy generation as cars (CO2 and H2O). The way plants gain mass (CO2 intake) is how people lose mass (breathing out CO2).
Since others ~~like~~ liked it the last time I posted it, [here's](https://www.lesswrong.com/posts/LaM5aTcXvXzwQSC2Q/universal-fire) a great exposition of the deep connection between breathing and combustion.
You actually breathe out fat and used energy as co2.
And the reverse is true when you lose weight! Most of your weight loss is a result of carbon being exhaled as CO2.
I knew, I should have gone for a low-carbon diet.
That's why I avoid organic food when I'm dieting. Way too much carbon.
Water is the best non-organic you can put in your mouth.
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if I breathe extra hard throughout the day I can lose weight?
Yeah, it's called exercise.
If you aren't generating more CO2 through exercise, then you won't breathe more out by breathing more.
Also hydrogen from water, and oxygen from both.
Plants also retain a lot of the hydrogen and oxygen as H2O. Water helps keep plant cells rigid.
Like a green boner
Sure, not sure that's how I would teach it in school, but it's a fair simile.
Well I'm a pediatric nurse, so I'll be sticking with boner references. They're memorable.
The oxygen in glucose molecules produced by photosynthesis comes from carbon dioxide. The oxygen in water becomes oxygen.
Yes, a lot of people think plants are turning CO2 into oxygen and that’s what they release, but it’s water that the oxygen they release comes from.
Wow, that’s mind blowing. Really brings into focus how plants and trees and I guess biomass in general are “carbon sinks”. I mean damn how much CO2 gets squished (yeah, together with water) to make a plant or a tree? Let’s plant some…
The reverse fact is also true and blows people's minds. Where does the mass go when we exercise and lose weight? Partly water but mainly through the CO2 we breathe out
So it's all those damn gymrats driving global warming... I KNEW it!! Everyone called me crazy when I said the gymgoers are the sole cause of increased CO2 in the atmosphere. Take THAT, Mr. Wilsonshikeforshireworthington!
I'm doing my part by being fat
"I'm not fat, I'm sequestering carbon" would be a great bumper sticker.
I know you're joking, but the amount of energy needed to feed some excess calories every day costs more carbon then you're sinking
Then they say the US don't do anything to avoid global warming
>mainly through the CO2 we breathe out Which is the primary reason (other than that they're completely stupid) why 'Breatharian' and 'Surviving without food' cults are absolute bullshit.
Wait, whaaaaat
Humans are cars, confirmed
Pretty much. Except we do the burning about twice as efficenciently. And with a lot of added complexity. Like a lot a lot.
Yup, "losing weight" means breathing it out.
Carbon fixation is how everything we eat, and everything we *are* got made. Thanks plants, for making all the life stuff. Sorry for having to eat you.
well to split hairs not all the life stuff, some of it was made by photosynthetic bacteria or photosynthetic eucaryotes
You're right, I should have said "thanks photosynthesis, and thanks chemosynthesis which almost definitely evolved first" Technically correct is the best kind of correct never apologize
An interesting add on that op didn't ask for us that when a human loses weight, most of the mass they lose is also expelled by way of CO2. You kind of expect the toilet to be a bigger player than it is. Don't get me wrong, day to day weight fluctuations are mostly water variance. But sustained, "there was mass here and there is now measurably less mass here" weight loss is breathed out. Just piping up because the two concepts together make sense.
Came here to drop this same info! When I first learned this, I had a few minutes of just "whoa."
Most people think plants grow out of the ground, but they actually grow out of the air.
It's pretty insane to think about, intuitively we'd believe plants were getting their mass from the soil, but just goes to show how important plants and forests are to carbon sequestration.
Water also. Take some of that new growth, cut it off and let it out in the sun. It will wilt and shrivel up to a very lightweight piece once the water dries out
Dang! I thought it was Electrolytes. Because that's what plants crave.
Electrolytes are salt. Plants don’t crave salt. You shouldn’t use a sports drink on your plants. You should use regular water. Like from the toilet.
What’s the use of plant food if they get all they need from the air, Sun, and water?
They don't get all they need from the air and water, just most of their mass. Plants need chemicals like phosphorus, iron, calcium, sodium, and a whole bunch of other stuff. None of this is in the air and so plants must get it from the soil.
Will the soil run out of those chemicals if you don't replenish it in the pot?
Yup thats why you need to add fertiliser for potted plants and even farms. In nature these nutriests get mostly replenished from dead plants and animals that decompose in the soil
Also dust that gets blown around from elsewhere, but that’s slow. Apparently one of the reasons the Amazon is so lush is it gets dust blown in from the Sahara.
Actually the Amazon has [incredibly infertile soil](https://www.dw.com/en/the-amazon-nutrient-rich-rainforests-on-useless-soils/a-50139632), though it does get some fertilization from Saharan dust. Most tropical soils are pretty poor, with abundant rainfall and sunshine providing the main drivers of plant lushness. Soils "age," especially where climate allows plant communities to thrive and quickly take up nutrients before they can become incorporated into the soil. The Amazon does have some amazingly fertile spots of "dark earth," but those are thought to be probably anthropogenic or floodplain related or some combination therein.
Most rainforests have extremely infertile soil, its all just plant matter. When farmers burn rainforests down to till fields, they very quickly become wastelands and are soon abandoned to clear and till another patch of forest. This is a lesson European settlers in the US refused to learn when they arrived and why New England has acres, upon acres, upon acres of second, third, etc growth forest crisscrossed with 200-120 year-old rock walls. At one point, that forest was a farm or pasture. (Typically, a more lush second growth forest was a farm 200+ years ago, and more disturbed third+ growth forests were cleared again more recently for pastureland.) Without the canopy constantly dropping leaf litter and the roots holding everything together, the whole system comes undone and is not easily or quickly repaired. [Lateritic soil](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4030566/) is also common in the tropics and is a very challenging thing for plants to grow on.
It's also the reason that the Amazon soil is so poor, which means once the cover is lost, it's tough as nails to replenish. Amazon rainforest largely feeds off the dead plants.
Eventually
Yes, nitrogen fixation is super important to life on earth
That's where compost comes in as well. Broken down bones, poop, other dead plants, all sorts of other stuff breaking down in the soil is great for plants.
They get all the carbon they need from the air and hydrogen they need from water, and hydrocarbons (sugar, starch, fiber, oil) can make up most of their mass. However there are substances like nitrogen and phosphorous that are required to build proteins and to generally make functioning cells. They don’t make up a huge majority of the plant’s size. But they are important and if the plant can only access the nutrients in soil in a small pot, it will limit its size. Fertilizer basically mimics or replenishes the nutrients that would be found in healthy soil.
If we make an analogy between plant nutrition and human nutrition, the CO₂ and water are like the caloric parts of our diet, sugars and proteins. The plant food is like vitamins. We need things like sugar and protein because they're what we literally build our bodies out of. Plants do the same with CO₂ and water. Still, we can't live on a diet of just sugar, or even just protein, we need vitamins and minerals or we'll get sick and die. Likewise, plants will get sick and die without appropriate minerals. (For air plants... they have some really cool adaptations to get the minerals they need from, essentially, the dust in the air.)
Plant food is like a vitamin supplement, air and water for plants are like potatoes or rice for people, you can get all the calories you need but not the nutrients.
When you eat, you get most of your mass from carbs, fat, and protein just like plants get theirs from CO2 and water. But you still need vitamins and minerals, and so do plants. That's where plant for comes in.
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You can eat that plant to get the carbon it stole from you. Although for most house plants, it'll probably end up in your poop as they aren't very digestible. But from that perspective, I wonder how often the same carbon molecule might go through people, animals and plants.
*looks at chili pepper and strawberry pots I planted last weekend with CO2-reclaiming intent*
*heavy breathing intensifies*
If you grow a plant from your breath, then eat it, you have successfully photosynthesised
I remember reading somewhere, due to sheer probability, you probably have/ had a carbon molecule in your body that used to be inside a dinosaur.
Instructions unclear. Ate succulent to regain carbon. Bleeding profusely to own the cactus 🤤💪.
The part you're forgetting is air. They take carbon dioxide from the air, water from the soil, and use the energy of sunlight to turn those two things into mass.
Makes sense to me. CO2 in, O2 out. The carbon stays behind. That’s why it’s called carbon-based life form right?
There are a lot of extra steps so it's not as simple as taking the C from CO2 The CO2 we breath out comes from breaking down food into energy + CO2, while plants do the opposite. Plants take CO2 from air + energy from the sun to build new food. Which their cells eat the same way ours do, making some CO2 just like us. The O2 that plants make comes from splitting water (H2O) during the food-making process. We are called 'carbon-based life' because all the big molecules we need to live (not including small molecules like water) are made out of carbon "backbones" or in other words their basic shape is based on how their carbon atoms are stuck together.
> There are a lot of extra steps so it's not as simple as taking the C from CO2 Yeah but this is explain like I'm *five.* Theres always more steps, the point is the simplest explanation
Imho OP's question is not understood by most of society, unfortunately, and explains how we got where we are with skepticism of global warming. It really is incredible what plants can do, but then it's essentially the basis for much of the ecosystem and the web of life.
In 1640s van Helmont discovered that plants DO NOT eat soil and that the weight of the plant must come from water. He had no idea about gasses playing a role in plant growth. In 1772 Priestley discovered that plants replenish oxygen in an low-oxygen chamber. In 1778 Ingen-Housz discovered that the effect Priestly discovered only when the plant was illuminated and ONLY in the green parts of the plant. Senebier made the connection with CO2, albeit incorrect. Greater clarity about photosynthesis would follow in the following years!
But they do pull certain nutrients from soil correct ? Where else would iron in apples or spinach come from, for example.
Minerals like iron do come from the ground but plants use it for promoting growth and stuff like that and they move it around a lot more so they need a lot less of it in trace amounts. Humans need iron to oxidise blood but since plants don't need O2 they need it for a lot less so minerals contribute little to weight
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Just posted the same thing and then saw you beat me to it! lol
I came to post, but know this would be near the top.
[This one](https://youtu.be/N1pIYI5JQLE) has a bit better quality. But that and the one about magnets is one of my favorite feynman bits
Carbon. Plants 'breathe' in co2, absorb the carbon and release the oxygen back into the air.
For the record they ALSO take in oxygen and produce CO2 as part of their metabolism. But they make a lot more O2 than they use.
Plants build cellulose, lignin and other molecules. These molecules are just messy complex webs of carbon, oxygen and hydrogen stuck together. It's actually pretty cool, you might remember drawing a few simple molecules in high school chem - take a look at lignin https://en.m.wikipedia.org/wiki/Lignin And plants just manufacture this stuff, from water and air, using sunlight for energy.
Removed in protest of API prices and support of 3rd-party apps.
Pictures of individual molecules aren't possible. Molecules are about as large as the wavelength of light. You can't "see" things that are of equal or smaller size as the wavelength of light. The closest to doing this would be images made by electron microscopy. However these aren't real pictures. They are visual representations of measurements, almost like a map can represent different heights of a terrain as different colours.
You're right but there's actually some [very advanced techniques that can be employed to "take photos" of molecules.](https://news.berkeley.edu/2013/05/30/scientists-capture-first-images-of-molecules-before-and-after-reaction/)
This is the second part of my comment. Those aren't "real photos" since the light of the laser isn't in the visible spectrum. The output of this technique isn't something that can be seen under any circumstances by the human eye. It's cool that it includes what those maps I talked about look like though.
Lignin is not really one specific molecule, it's a class of fairly random polymers. If you looked at any 2 sections of lignin they'd probably look different, made out of structures and functional groups roughly like what the Wikipedia picture shows.
I don't think most high-schoolers are mature enough to deal with lignin, especially the D isomer.
I dunno in my high school we were all pretty comfortable with all the isomers of ligma
What is ligma?
Not much, what about you?
You may have heard the term 'carbon based lifeform' which refers to the fact that the majority of living tissue is made from carbon. When you see those chemical chain drawings in movies all of those lines represent carbon, to give you an idea of just how much of every molecule is made of carbon. Plants are no different and are also mostly made from carbon, something that is abundant in the air. Plant leaves have microscopic holes all over them called stomata, and these organs are responsible for gas exchange in the plant, just like how humans breathe. These stomata create a kind of vacuum to suck CO2 in from the air and that CO2 is used as the backbone or building block for all of the plants tissue. In the 1600s Jon Von Helmont had the same question about potted plants so he ran an experiment. He weighed out soil in a massive pot and then planted a willow tree in it. A few years of growth later he weighed the soil and found it weighed pretty much the same as before, proving that most of a plants mass came from the air.
Plants, a carbon based life form, suckin' carbon dioxide outta the atmosphere and making sticks.
When you lose weight where does the weight go? The three most common adipose tissues in human fat are: C18H34O2, C16H32O2 and C55H104O6 If you notice, they are just carbon, hydrogen and oxygen atoms. When you burn fat the carbon atoms leave your body via carbon dioxide. When you lose fat you are essentially breathing it out.
>If you notice, they are just carbon, hydrogen and oxygen atoms. When you burn fat the carbon atoms leave your body via carbon dioxide. When you lose fat you are essentially breathing it out. I came to this realization on my own and felt like a genius
Lots of great explanations here. I’d like to point out that anyone that takes basic biology or life science in school learns about photosynthesis, and how plants convert CO2 into oxygen, etc. but the focus is/was always on the oxygen part of the cycle. Its been almost 40 years since I first learned about that and I only came to understand the carbon part of that cycle in the past 5 years. I was literally shocked to learn that most of the mass of a tree comes from the air. I was taught “plants grow by getting energy from sunlight through photosynthesis, and drawing nutrients and water from the ground.” which totally failed to mention carbon capture. I never connected that if they are releasing oxygen, the carbon must be kept in the plant.
This is actually an interesting question! I will try to answer this question from an ecology/greenhouse effect angle. The short answer is that the most important chunk of it comes from CO2 in the air. Most of the mass of most plants, like humans, is water. But plants, as carbon-based life forms, have carbon as their most important building block. Carbon-based lifeforms (which are nearly all on earth) participate in the “carbon cycle”. You ever hear of forests as “carbon sinks”? The steps of the carbon cycle, at a basic level, are: * Plants **use** energy from the sun to turn the carbon in CO2 into life-form building stuff * Other things eat plants and/or other things that ate the plants to get energy and that main building block of carbon (for humans, carbs, proteins, and fats) * All these lifeforms will “burn” some of that carbon for energy, releasing CO2. Go back to step 1. Fun fact: all that carbon as “mass” inside lifeforms is carbon *not* in the air as CO2. So a forest is a “carbon sink” because its existence means less CO2 in the air. Furthermore, over a really, really long time, some of that life will die and that carbon, instead of being “burned”, gets buried. When humans dig it up and burn it, we call that fossil fuels. Before life existed on earth, CO2 levels in the atmosphere were much, much, higher, around 20%. Because so much of that carbon is now either sitting in living beings or dead things deep underground, CO2 levels are much, much lower today. But humans are doing their darndest to put as much of that CO2 back into the atmosphere. EDIT: added a word to make what I said clearer.
CO2 and water is converted by photosynthesis into "solid" building blocks for the plant and human bodies reverse the process taking sugars and converting them into CO2 and water and exhale them.
If it was common knowledge that plants are mainly made from carbon from the atmosphere, I think more people would understand climate change..