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Where does a tree get its mass?

thelastpsychiatrist.com

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Re: Where does a tree get its mass?

#31
post #30

stupid mode Opens up more questions than it answers. It seems when trees die, they become earth or even oil. How come they don't completely dissolve into air again? And if they don't completely dissolve into air, how come all the CO2 is not bound in the earth yet (trees pluck it out of the air, then die and bind it to the ground)? There would have to be bacteria or something that converts soil into air (CO2), but the…

Trees do dissolve. Forest fires are the most elegant way -- the reaction liberates much of the carbon and all of the oxygen into gasses including CO2, and the cycle is complete.

Bacteria that break down the rotting remains of a dead tree also consume the energy stored in the cellulose and release gasses like carbon dioxide and methane. At some point the remains don't contain bonds with easily freed energy and you have regular old dirt. If they had a way to break down the dirt further they would, but the cost is too high.

Re: Where does a tree get its mass?

#32

Earlier quoted context omitted.

Except the example he gave was also wrong. 3 + 4.2 is 7.2, using exact arithmetic, which should be the default assumption. If you're measuring values under uncertainty, then his explanation makes some sense. But that's a property of measurement and uncertainty, not of numbers or arithmetic.

Default assumption for whom? For a scientist, or someone working with real world data, this should never be the default assumption. Besides, in the paragraph with the arithmetic he explicitly talks about significant figures. In context, the answer is unambiguously 7 .

It's 7.2. Without context (and he gives none for the expression) everyone (including me as a scientist) must assume abstract numbers. What's more, we know he's not using measurements because there are no units...

Re: Where does a tree get its mass?

#33
An interesting thing here is that this article assumes that the way science is taught is wrong. I do not intend to make any conclusions about this, but I just graduated from high school and I just realized why people don't learn science as opposed to a bunch of meaningless phrases.

Although a lot of it is a broken system, but the truth is that they aren't expected to. What is expected of them is to get good grades, and since that is possible through rote almost all of my peers take that route. If you ask them in a moment of honesty they say; "why should I do it? I'll just get the grades get into a good college a good job... Why should I waste my time learning this?".

I used to gripe about the system whenever I heard that reply and why they just didn't get it, but now I realize that they are simply reflecting society in general. Most parents quite frankly don't care that they know science or anything as long as they get good grades. Most teachers hardly give a damn about teaching and they aren't even remotely interested in science. Most employers upon employment cannot check and do not look at how much the individual understands anything. They just ask for a degree from a reputable institute.

I admit that it is harder to change the mindset of a population, but this is something that has to be done. Changing the school system and bringing out new books will have limiting impact unless the foundations of this problem (societies attitude toward learning) aren't addressed.

Re: Where does a tree get its mass?

#35
post #18

As far as I know, most of the CO2 in plants goes to respiration for energy production. Not saying it doesn't go to mass, as well, but it's the energy side of things that people learn in elementary school. We're not stupid, and this man needs to think about his accusations before he blogs about them...

Are you aware that cellulose is just interlinked glucose molecules? A tree is basically a giant hunk of hydrated sugar byproducts with some minor mineral and other components.

Re: Where does a tree get its mass?

#37
post #18

As far as I know, most of the CO2 in plants goes to respiration for energy production. Not saying it doesn't go to mass, as well, but it's the energy side of things that people learn in elementary school. We're not stupid, and this man needs to think about his accusations before he blogs about them...

And what does a tree do with this energy? It's not a light bulb.

It uses the energy to split the oxygen off of the CO2, splits the oxygen of off water, and makes hydrocarbons from the C in CO2 and the H in water. The oxygen is released as waste (a small amount is used).

So all the energy used in a tree is devoted to making its mass.

Re: Where does a tree get its mass?

#38
post #17

Feynman knows: http://www.youtube.com/watch?v=N1pIYI5JQLE

Can't upvote you enough for this. By the way, Feynman also knows the difference "between knowing the name of something and knowing something": http://www.youtube.com/watch?v=05WS0WN7zMQ

More Feynman on the same topic ("Energy makes it go"): http://physics.gu.se/~f3aamp/teaching/wakalix.html

Re: Where does a tree get its mass?

#39

An interesting topic, but I couldn't get more than a few paragraphs in. It's really poorly written. EDIT "couldn't" (I suppose if I'm going to gripe about grammar, I should at least proof read...)

I stopped reading at "Whatever you just said, it's wrong" as it was evident from there that it was the usual HN hyperbole article. Not to say HN is dominated by such articles, but their number has been steadily growing and one is already too much.
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