Physics has the conservation of mass right? … And … Things like trees sit in the ground. Where do they get the mass to grow tall? How do they move it up their trunk? How do really old trees get more dirt when they make it into trunks?
In: Biology
They actually get all the stuff from the air.
They can turn, using photosynthesis water and co2 into sugar, and then turn the sugar into other stuff like wood and leaves
Trees pull water up their roots, and that water carries all the vital nutrients they need to grow and thrive. Combining that with photosynthesis bringing in all the energy they need, plants and trees have it pretty good. All that root action brings up nutrients and chemicals that have been deposited by dead and decaying animals and plants.
All that mass is kind of like our human skin. All the outer layers are dead, and the new/forming layers gently push them out from the core.
> Where do they get the mass to grow tall?
Not from the dirt! The vast majority of the mass which makes up plants including trees comes from the air and water.
Cellulose, the main structure of the tree, is composed of carbon, hydrogen, and oxygen. The carbon and oxygen can come from the air, while water of course contains the hydrogen and more oxygen.
> How do they move it up their trunk?
Water moves up the trunk of the tree via capillary action, water’s surface tension, and something called “transpiration”. Basically water evaporates from the bottom of leaves and this acts to pull water into the leaves from the trunk, and by extension all the way from the roots.
Trees are mostly made out of air and water.
6 CO2 + 12 H2O + photons → C6H12O6 + 6 O2 + 6 H2O
Trees take in CO2, water and light. The use photosynthesis to create glucose and oxygen. The oxygen is released into the air. The sugar is used for the tree to grow.
They don’t use the dirt much to grow. They only take small amount of minerals from the dirt.
Trees are made of carbon and they get essentially all of this carbon (C) from the air they breathe in and then they breathe out oxygen (O) which is how we breathe.
This might seem odd, but we actually do the essentially the same but in reverse. If you have ever heard that you breathe in O and breathe out carbon dioxide (CO2). This is a mix of C and O and actually comes from the food you break down and the fats that you burn. So trees gain mass from breathing in C in the same way that we lose it as we breathe out C, humans have almost the same reactions as plants but in reverse.
As to how they move their mass around, trees mostly breath through their green leaves and then the carbon is transported around the tree through different cells. This is why trees don’t grow in winter when they lose their leaves, but spark up again in spring.
From the Air! Richard Feynman is very excited about your question and gives a great explanation.
[Feynman on trees](https://youtu.be/ifk6iuLQk28)
Short answer carbon from the atmosphere. Long answers still the same but technically difficult to describe.
This isn’t directly answering your question but kind of related – it’s a fun a fun fact I learned when I visited the redwoods in Northern California. I had always thought trees get their water from their roots in the ground but the reason that redwoods get so tall is they also absorb water from the mist in the air.
Another fun fact about redwoods, when they fall down, the branches sticking up can grow into new trees. About 80% of them that you see today are clones and grew that way as opposed to from seeds. You can trace the dna back to a single seed as long as 30,000 years ago for some.
https://www.google.com/search?q=veritasium+tree+mass&oq=veritasium+tree+mass&aqs=chrome..69i57.6409j0j7&client=ms-android-verizon&sourceid=chrome-mobile&ie=UTF-8#
Great video on it that explains everything! Check out his other videos too, I put this guy on the same level as smarter every day and vsauce!
This is the best ELI5 explanation provided by Nobel award winning physicist Dr.Richard Feynman to this question https://youtu.be/ifk6iuLQk28
If you do have the time watchthe entire interview it’s an entire sequence of some of the best questions answered in an ELI5 fashion.
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