Where Does A Tree Get Its Mass?
The common answer is: from the soil, which is wrong.
The mass of the tree comes from the wood (cellulose), and cellulose (by weight) is carbon. Carbon comes from the air (CO2).
I.
The first question you want to ask, right now, is why this now obvious answer wasn't obvious to begin with. More specifically, why you know the word "photosynthesis" but not how to apply it, at all.
Why were we taught photosynthesis? First, most of us don't remember anything about it anyway. If we do, we have recollections of certain unconnected concepts:
- sun gives "energy"
- plants "take up" "sunlight"
- they "breathe" CO2 and "release" O2
- It's good to talk to plants
The quotes serve to suggest we don't even really know the meaning of the terms we learned.
None of those statements are informative, nor can the be applied to reality (e.g. answering the above question.) It's not that you forgot; it's unlikely you could have answered that question even back when you were learning photosynthesis.
Yet-- and this is the point-- the word "photosynthesis" is in your head. You learned a made up word, an artificial carve out of what is really a fluid physical process. You didn't learn any of the reality.
So, on the one hand, we actually didn't learn anything. And, on the other hand-- the worse hand-- we actually think we know something. Not just ignorant; but ignorant and deluded.
II.
But "tree mass comes from the air" isn't actually right, either. Some trees are more than 50% water by mass, so the mass of a tree would indeed come from the ground. (No partial credit: if you said "from the ground" but were thinking "minerals" you were still wrong.)
Indeed, this question reveals that even with a general background in science, and two acceptable answers, most people still get it wrong. So what, exactly, was the point of the general background in science, let alone photosynthesis?
In other words, you don't really appreciate that a) a tree has water mass; b) air has mass.
I state it here, and you "know" it, but that's not the same as it being a fundamental part of your worldview, the way "the sun is hot" or "the earth revolves around the sun" does, fundamentals that allow you to make guesses about reality. That's what science should have given you; instead, it gave you a hodgepodge of disconnected linguistic propositions that neither describe reality nor predict reality.
"Where do plants get their energy?" "Photosynthesis." Nothing happened there, except words.
Here's an example: if, prior to this post, I had asked why a helium balloon, despite weighing something, floats, you'd have to reason out an answer. But just my saying, "air has mass" makes the question easier to answer. You already know air has mass, you don't need me to tell you; but you don't feel it-- that's why my telling you here makes a difference.
I hardly need point out how a discussion about global warming is vastly altered if it is intuitively understood that trees get their carbon from the air.
III.
But, actually, both of those answers are wrong: the question itself is meaningless. It is too vague, allows for multiple different interpretations and answers, is simultaneously misleading and oversimplified.
The bigger problem-- and this applies not only to science but to any field furthered by a dialectic-- is that we demand precision in answers, and allow-- expect-- imprecision in the questions.
"Where does the dry mass of a tree come from?" would be a little better. Etc. But no one worries about this; indeed, many shrug their shoulders, "yeah, the question is vague, but we all know what it means." Well, evidently not.
It barely requires exposition that psychiatry suffers greatly from this problem, the haziest and laziest of terms and definitions magically generating concrete and specific responses. Internist asks me, "I have a patient who is bipolar, what should I do?" If I say anything other than "Depakote" or equivalent, he thinks I'm being an ass. But my answer is 100x less relevant than understanding what he means by either "bipolar," "patient," or "do."
Politics, I need not point out, is worse. The most asinine questions are expected to generate meaningful responses. "Should we bail out General Motors?" Which one of those words actually means what you say it means? Who is "we?" What's a "bail out?" "General Motors" the whole company, the pension division, the new plant they opened in Russia, what? But if you ask for any clarification, you're being difficult. You don't get it.
IV.
A final analogy may be here helpful. You may also (not) remember from school "significant digits." For example, 3 + 4.2 = 7. Since "3" only has one significant digit (3.0 is a more precise number with 2 significant digits) the answer itself can have no more than one significant figure. Importantly, it's not that "7" is an okay answer, but really 7.2 is more precise. 7.2 is wrong, because that 3 could have been 3.4, 2.6, etc.
Or, more generally, an answer cannot be more precise than its data. Or its question.
The first business of science education should not be to help us answer questions, but to help us ask questions.
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November 18, 2008 8:07 PM | Posted by : | Reply
This is such an important concept for people to learn that an enormous number of even intelligent people don't get. The following two posts by Eliezer Yudkowsky make a similar point on the overcoming bias blog:
Fake Explanations: http://www.overcomingbias.com/2007/08/fake-explanatio.html
Mysterious Answers: http://www.overcomingbias.com/2007/08/mysterious-answ.html
November 18, 2008 9:19 PM | Posted by : | Reply
I knew the right answer, but only because I studied in a class on biotechnology for four years.
Yesterday I was at a client's, one who is intensely religious and intensely right wing, and he's going on about the economy. Finally he looks at me and says "You know what's causing all this recession, right?" to which I wanted to reply "No, actually I only have the vaguest fucking idea how something like this happens, and what little I can say I understand comes from a Tom Wolfe book I didn't enjoy." but instead nipped that to a simple no.
I half expected him to fly his true colors and say gays or Jews, but instead he blamed it on the upswing of oil prices. He seriously seemed to believe that this one thing could have caused this, all on its lonesome. Naturally it was preceded with one of those statements you learn to be an indicator of something stupid about to be said- "I don't claim to be the smartest man in the world, but it's pretty clear to me...".
Of course, this same guy once launched into how the earth isn't as old as we think it is, because it was "proven" that the speed of light isn't a constant, invalidating carbon dating.
November 18, 2008 9:26 PM | Posted by : | Reply
Where does a tree get its mass? Current theory suggests that mass is a result of the (still undetected) Higgs Boson, interacting in some not-yet understood means with the fundamental fabric of the universe. Because we don't understand that interaction, we call 'mass' a basic property of matter.
And you, sir, are a pompous poseur: a statement I believe to be both precise and accurate.
November 18, 2008 10:21 PM | Posted by : | Reply
dugg. and i agree with the first commenter. ob is a fantastic blog that talks about this type of thing quite frequently.
November 19, 2008 12:27 AM | Posted by : | Reply
"And you, sir, are a pompous poseur: a statement I believe to be both precise and accurate."
Mr Flinthart, could you please elaborate on your affirmation? Your previous explanation is just a valid answer to one of many ways of taking that question. I could tell you you're right, as I can tell you you're wrong, but that's not the point.
The point here is "Why is that the question", "what does it entail" and "what would be the right answer based on those facts" if there was any question at all. Those set the question in a context where it can be studied and thus a correct procedure can be followed.
Maybe asking you "Where does a tree get its mass" leads to nowhere in the current economic situation. "Why is there an economic recession" would be a question, if we knew exactly what a recesion entails and thus what we are asking. The problem is that in the midst of all these naming process, there are certain disconnected facts that carry significance that can't really hold upon themselves because they are general terms that may or may not even apply at all to what we want to solve, or at least in the way we wish they would, hence, the question about bipolarity, which, in itself isn't a simple diagnosis.
Sorry, english isn't my native language.
November 19, 2008 7:01 AM | Posted by : | Reply
You guys are a lot more fun than politicians. Depending upon what my meaning of "fun" is I suppose.
November 19, 2008 10:03 AM | Posted by : | Reply
I did know that air has mass, but obviously not in a way to correctly answer the question, yet also not only in the facile "helium floats" way that you suggest.
I began cycling competitively this year (triathlons, actually), and it is impossible to develop even a superficial understanding of the importance of aerodynamics without first grasping the basic fact that air is "in your way". When riding, I still imagine myself knocking millions of "bits" of air out of my way, like tiny bowling pins.
November 19, 2008 1:15 PM | Posted, in reply to , by : | Reply
I'm not surprised that Yudkowsky has some good things to say on the subject. Considering the amount of time that he's put into breaking down the idea of intelligence, he'd damn well better have some good insight, eh?
Honestly, I think everyone should at least try to work through Levels of Organization in General Intelligence. It's pretty powerful stuff.
November 19, 2008 4:12 PM | Posted by : | Reply
Is it weird that, when I first read the title, I thought you were asking which Catholic priests minister to trees?
November 19, 2008 7:46 PM | Posted by : | Reply
Nicely asked and illustrated. You might then go on to ask, in the face of imprecise questions, "why has this been posed to me in this way?" and perhaps speculate as to the motives of the questioner...
I'd love to bail out GM, if it means I get a free Corvette that my kids' grandchildren have to pay for. What are childrens for if not to ensure our own comfort and enjoyment?
November 20, 2008 2:59 AM | Posted by : | Reply
I'm happy to see another post along these lines of "what the #@!%#?" It's taken me well over a day to conclude I don't even have enough of a POV to pose a question, well asked or not.
For some unfathomable reason, I look forward to your next post. Seriously.
Sigh.
November 20, 2008 2:05 PM | Posted by : | Reply
I may have been reading too long when I saw that question and though: Last is asking a trick question again.
November 20, 2008 2:52 PM | Posted by : | Reply
The real question is where did my cock get its mass? Answer? A gift from the heavens above. The chicks dig it.
November 22, 2008 12:37 PM | Posted by : | Reply
As Will Rogers is supposed to have said "It's not what people don't know that hurts them. It's what they do know that just ain't so." I suggest this as a motto for your blog, in the event that you get tired of people asking you what the German means. It's particularly appropriate in that I can't find evidence he actually said it…
February 19, 2009 8:48 AM | Posted by : | Reply
Feb 19 09 Reuters news story: with all of this available carbon, trees are getting bigger:
this link may work for a while
http://www.reuters.com/article/scienceNews/idUSTRE51H5KE20090218
Otherwise google "Forests absorb 20 percent of fossil fuel emissions: study. Michael Kahn."
March 16, 2009 8:24 AM | Posted by : | Reply
The problem seems like language isn't designed for this kind of precision. We have thousands of words that are meant to define things specifically, but they REALLY just relate a particular word to something you've experienced. Since everyone's experiences differ slightly, the meaning of words will differ slightly between people.
For some words the difference will be infintesimal or non-existant. Everyone has basically the same experience of the sun, so the word 'sun' is more or less the same for everyone. Its directly related to an experience. So is 'fire truck'. But things like 'life', 'mass' are more abstract, and can't be directly related to something in the world. You have to assemble several different ideas together to get their meaning. As words get more abstract you have to relate them to more and more experiences to get their meaning, and so their use will differ more and more between people.
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