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"Earth Science as a Vehicle for Illuminating the Boundary
between the Known and the Unknown"
by Kim Anne Kastens
Lamont-Doherty Earth Observatory
of Columbia University
Palisades, NY 10964
Adapted from Journal of Geological Education, 1995, v.43,
(Note: This article is adapted from the keynoteaddress presented
at the joint meeting of the Northeast and New England sections of
the National Association of Geology Teachers, May 21, 1994, Nyack,
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A pervasive theme throughout my recent conversations about science
education has been "Sciencing" as a verb, "science" as a process
rather than as a collection of facts. But in truth "science" is
not a single process; it is a collection of interwoven processes.
To help our students adopt this alternative perception of science,
we obviously need to help them understand and experience the processes
of hypothesis formation, of experimental design, of collecting and
analyzing and interpreting data. I think that in recent years, the
teaching profession has made great strides at helping students to
understand those processes. In this article, though, I'm going to
focus on another profound aspect of the "process" of science, an
aspect that has not been emphasized as much: the process of finding
a solvable question. Of all the infinite number of questions that
can be asked about the earth, only a small subset are solvable at
any given moment in human intellectual history. A solvable question
is, first of all, a question that hasn't already been solved, and
secondly, a question that can be solved with techniques and understandings
that exist or that can be developed.
It turns out that this special set of solvable questions cluster
together. The place where they cluster constitutes the boundary
between the Known and the Unknown. To me, human knowledge seems
like an ameboid shape (figure a).
Inside is everything that is known or understood by human beings,
by at least by one human being, somewhere in the world. Outside
is every thing that is not known at all, by any human being, anywhere.
The pseudopods of the amoeba represent branches of human knowledge
that have progressed quite far into the unknown (figure b).
The embayments are branches of human knowledge that are temporarily
lagging behind adjacent lines of inquiry. In general, throughout
human history, the ameba has grown--the volume of the Known has
expanded at the expense of the Unknown (figure c).
During occasional dark ages of human history, the ameba contracted
as books were burned or intellectuals were persecuted. I have drawn
the amoeba in two-dimensions. But in truth must be a multidimensional
shape, a shape intricate enough to represent every line of inquiry
in every branch of knowledge. I envision this boundary as having
some tensile strength, like a stretchy membrane (figure d).
The stretchiness inhibits growth of the ameba -- energy must be
expended to push back the frontier between the known and the unknown.
As a given pseudopod, a given line of inquiry, is pushed farther
and farther into the unknown, the bounding membrane is locally stretched
more and more drastically, and the energy required to expand the
domain of the known in that particular direction rises rapidly.
The easiest advances occur in the embayments, in those branches
of knowledge that lie between the farthest stretched pseudopods.
I have drawn the boundary between the known and the unknown as a
solid line, but in truth it should be drawn as a zone of finite
thickness (figure e), where the thickness represents the transition
from the point where the first human being on earth has the first
glimmerings of comprehension of anew truth, to the point where the
understanding is generally shared by specialists in that branch
Scientists live and work within this boundary; we dance on the
interface between the Known and the Unknown. Students bump into
this boundary occasionally, but generally they are only dimly aware
of its existence or location, even when they are standing on it.
Within that larger volume representing all knowledge of all people
everywhere on earth, one can draw a smaller volume representing
"common knowledge"--the things that most people know, from everyday
experience, from television, from newspapers, from movies, from
popular literature, and so forth (figure f).
Note carefully that the volume of common knowledge is not evenly
centered within the volume of all knowledge. Common knowledge is
closer to the boundary between the known and the unknown in some
branches of human knowledge than in other branches of human knowledge.
And in particular, common knowledge is close to the boundary between
the Known and the Unknown in Earth Science.
In a typical high school or lower-level college math course, everything
the student studies has been known for at least a century. In a
typical high school or introductory college chemistry course, almost
everything the student studies has been known for at least half
a century. A Chemistry or Physics major in college typically has
to persevere through three or four years of coursework before he
or she can even begin to understand the questions on the cutting
edge of the field, let alone understand the answers. The boundary
between the Known and the Unknown in chemistry and physics is very
far from the field of common knowledge.
Earth Science is not like that. In Earth Science, the boundary
between the known and the unknown is close-by; it's very accessible,
very understandable to the newest students on the very first day
of their very first Earth Science class. Why are there mountains
over here, but not over there? Will there be another ice age, and
if so, when? Why did the dinosaurs go extinct? Why are the oceans
salty? Why is there so much oil in Saudi Arabia, and none in Rockland
county? Where do diamonds come from? Where did the moon come from?
Why does it snow a lot in some years and not very much in other
years? These questions are at or near the frontiers of research
in Earth Science. Yet these questions can be understood by any student;
indeed these questions can be conceived and posed by any student.
Imagine or recall a circumstance in which a beginning student
posed a seemingly simple question about the earth, and a teacher
answered, truthfully, "nobody knows; nobody in the world knows the
answer to that question." I think that something really important
has just happened. That student has just bumped into the boundary
between the Known and the Unknown; that student has found his way
or her way to the place where science begins. From that starting
point, and while remaining entirely within the realm of concepts
and questions that students understand, we can explore where exactly
the boundary lies: "this is understood, this is sort of understood,
this is not understood at all."
Here's another way to think about this idea. Imagine now that
we sit physically rather than conceptually within the amoeboid shape
of human knowledge. Imagine that I am holding a flashlight, which
represents my personal knowledge, plus my communications skills,
plus my energy and enthusiasm and motivation, plus my instructional
materials, in other words the sum of all the resources I have available
to convey insight and understanding to my students. If I shine my
light in the direction of Earth Science knowledge, it's easy for
me to reach the frontiers of knowledge -- the boundary between the
Known and the Unknown in Earth Sciences is close to the field of
common knowledge where my students and I begin our exploration.
On the other hand, if I shine my light in the direction of Particle
Physics, only the feeblest illumination reaches the frontiers of
knowledge. I have the same light, representing the same depth of
personal knowledge, the same communications skills, the same energy,
the same quality of instructional materials, the same resources
in total. But the distance between our starting point in the field
of common knowledge and the frontier of Particle Physics is too
large -- my light doesn't reach. Similarly, if I shine my light
in the Biochemistry direction, it's still pretty dark over there
at the frontier of knowledge; the boundary between the known and
the unknown can only be dimly perceived.
In conclusion, I feel that we, as teachers of Earth Sciences,
have a special opportunity within the grand scheme of science education,
an opportunity that is less easily available to our colleagues teaching
in most branches of science and math -- we can illuminate the boundary
between the Known and the Unknown.