Plate tectonics / Tectonic plates
This might be a "Words Worth" sort of item...
I find that a certain subset of my students (i.e. the ones who don't do very well in my classes) make no distinction between the phrases "tectonic plates" and "plate tectonics." To me, these mean very different things, but to the undertrained geologist, they must appear synonymous.
What's the difference?
A tectonic plate is a thing, a noun, an object. It is a slab of the Earth's lithosphere that behaves as a relatively coherent block. It is not eternal. It can grow with the addition of new lithospheric material from neighboring plates along its edges (accretion) or fuse with another plate along a suture zone. It can also break apart discretely, as Eastern Africa is doing today, or diffusely, like the Basin and Range province of North America, where the crust is being stretched and thinned.
On the other hand, plate tectonics is a paradigm, a model for how the Earth works. It is a well-corroborated hypothesis that explains so many disparate phenomena it has earned the status of a theory. (And I mean theory in the scientific sense -- a seriously well-founded concept, on par with the theory of gravity, atomic theory, or the theory of evolution by natural selection: these are all hypotheses which have been repeatedly tested over many years and never falsified, so that they are our best working explanation of how a particular thing works.) It is a variety of tectonics in general, which includes non-plate-oriented explanations for building things like mountain belts and continents. Plate tectonics is an idea, an explanation.
Anybody else encountered the false conflation of these two different terms? I think it's going to have to be something that I address up front when I introduce plate tectonics in class, in the manner of A Private Universe -- assessing student worldviews and weeding out (nullifying) false conceptions as a necessary first step before you can sow correct ideas.
I find that a certain subset of my students (i.e. the ones who don't do very well in my classes) make no distinction between the phrases "tectonic plates" and "plate tectonics." To me, these mean very different things, but to the undertrained geologist, they must appear synonymous.
What's the difference?
A tectonic plate is a thing, a noun, an object. It is a slab of the Earth's lithosphere that behaves as a relatively coherent block. It is not eternal. It can grow with the addition of new lithospheric material from neighboring plates along its edges (accretion) or fuse with another plate along a suture zone. It can also break apart discretely, as Eastern Africa is doing today, or diffusely, like the Basin and Range province of North America, where the crust is being stretched and thinned.
On the other hand, plate tectonics is a paradigm, a model for how the Earth works. It is a well-corroborated hypothesis that explains so many disparate phenomena it has earned the status of a theory. (And I mean theory in the scientific sense -- a seriously well-founded concept, on par with the theory of gravity, atomic theory, or the theory of evolution by natural selection: these are all hypotheses which have been repeatedly tested over many years and never falsified, so that they are our best working explanation of how a particular thing works.) It is a variety of tectonics in general, which includes non-plate-oriented explanations for building things like mountain belts and continents. Plate tectonics is an idea, an explanation.
Anybody else encountered the false conflation of these two different terms? I think it's going to have to be something that I address up front when I introduce plate tectonics in class, in the manner of A Private Universe -- assessing student worldviews and weeding out (nullifying) false conceptions as a necessary first step before you can sow correct ideas.
Labels: plate tectonics, teaching, words
3 Comments:
"Tectonic plate" has no meaning in the profession, and I make a point of calling them just "plates" or "lithospheric plates" in my writing on About.com. Another common name is "crustal plates," but that can confuse students too because the plates are crust-mantle sandwiches. But really, try to avoid "tectonic plates" entirely.
To mirror Andrew's comment, I just use the term "plate". I didn't do this consciously to avoid confusing students; it's just the way I refer to them in general.
Don Anderson, in his "Theory of the Earth" second edition, says the plates are more like rafts of bubbles, prone to slump and stretch if not confined. Names are metaphors.
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