The take home of course, is that it is necessary to listen to the
students as they struggle with the new concepts been presented. That
will flush out already established error. From that starting point,
the teacher then has a chance to be effective.
Whenever we set out to change a paradigm in people's thinking, it is
the same problem. They already have a satisfactory solution in hand
that they have no reason to question. Electricity flowing like water
is a great idea and works very well. It just has zero connection to
physical reality.
Let us not forget Newton's work. It is totally correct until you
attempt impossible things rather distant from out Newtonian space.
The point I wanted to make here is that your preconceived notion is
not wrong so much as incomplete and lacking rigor and all that does
not matter if you never experience a need to know.
What this also tells us is that this type of test needs to be
selectively marked for weaknesses that the teacher can pick up on and
work with.
May 2, 2013 —
As part of an unusual study, Philip Sadler, the Frances W. Wright
Senior Lecturer in the Department of Astronomy, and colleagues tested
181 middle school physical science teachers and nearly 10,000 of
their students, and showed that while most of the teachers were
well-versed in their subject, those better able to predict their
students' wrong answers on standardized tests helped students learn
the most.
If you had to explain
what causes the change in seasons, could you? Surprisingly, studies
have shown that as many as 95 percent of people -- including most
college graduates -- hold the incorrect belief that the seasons are
the result of the Earth moving closer to or further from the sun.
The real answer,
scientists say, is that as Earth's axis is tilted with respect to its
orbit, when on its journey it is angled inward, the sun rises higher
in the sky, and that results in more direct sunlight, longer days,
and warmer temperatures. Distance plays no role; we are actually
closest to the sun in the dead of winter, during the first week of
January.
Why do so many people
continue to hold the wrong idea? The answer, said Philip Sadler, the
Frances W. Wright Senior Lecturer in the Department of Astronomy and
director of the science education department at the
Harvard-Smithsonian Center for Astrophysics (CfA), may be found in
what science teachers know.
As part of an unusual
study, Sadler and colleagues tested 181 middle school physical
science teachers and nearly 10,000 of their students, and showed that
while most of the teachers were well-versed in their subject,
those better able to predict their students' wrong answers on
standardized tests helped students learn the most. The findings
are described in a paper published last month in the American
Educational Research Journal titled "The Influence of Teachers'
Knowledge on Student Learning in Middle-School Physical Science
Classrooms."
"What our
research group found was that for the science that people considered
factual, teacher knowledge was very important. If the teachers didn't
know the facts, they couldn't convey them to the students,"
Sadler said. "But for the kinds of questions that measure
conceptual understanding, even if the teacher knew the scientific
explanation, that wasn't enough to guarantee that their students
would actually learn the science."
Sadler pointed to the
question of what happens to a lamp when the power cord is squeezed.
"Middle school
students say if you squeeze hard you will see the light gets dimmer,
even though they've stepped on that cord before, or they've put the
corner of their chair on that cord before, and nothing has happened,"
he said. "Their theoretical understanding of the way the world
works includes the idea that electricity is like water flowing
through a garden hose. If you put some pressure on the cord, you will
get less electricity out the other end. It turns out that for most
major scientific concepts, kids come into the classroom -- even in
middle school -- with a whole set of beliefs that are commonly at
odds with what scientists, and their science teachers, know to be
true."
If teachers are to
help students change their incorrect beliefs, they first need to know
what those are. That's where the standardized tests developed by
Sadler and his colleagues come in. Multiple-choice answers were
gleaned from hundreds of research studies examining students' ideas,
particularly those that are common -- such as electricity behaving
like water.
For the study
described in their paper, Sadler and his colleagues asked teachers to
answer each question twice, once to give the scientifically correct
answer, and the second time to predict which wrong answer their
students were likeliest to choose. Students were then given the tests
three times throughout the year to determine whether their knowledge
improved.
The results showed
that students' scores showed the most improvement when teachers were
able to predict their students' wrong answers.
"Nobody has quite
used test questions before in this way," Sadler said. "What
I had noticed, even before we did this study, was that the most
amazing science teachers actually know what their students' wrong
ideas are. It occurred to us that there might be a way to measure
this kind of teacher knowledge easily without needing to spend long
periods of time observing teachers in their classrooms."
To help teachers hone
this knowledge, Sadler and his colleagues have made the kind of tests
used in their study publicly available. More than a dozen tests
covering kindergarten through grade 12 are downloadable here, after
completing a tutorial on their development and interpretation.
Going forward, Sadler
said he hopes to conduct similar studies in the life sciences,
particularly around concepts such as evolution and heredity. He also
plans to study what types of professional development and new teacher
preparation programs help improve instructors' facility in knowing
what their students know.
Ultimately, Sadler
said, he hopes teachers will be able to use the tests to help design
lessons that change students' incorrect ideas and help them learn
science more quickly and easily. This is particularly important as
states adopt the recently released Next Generation Science Standards.
"State
certification for teaching science might well include making sure
that new teachers are aware of the common student misconceptions that
they will encounter, as well as being proficient in the underlying
science," said Sadler. "Prior to this, there has never been
an easy way to measure teachers' knowledge of student thinking, while
we have probably been placing too much emphasis on testing for
advanced scientific knowledge.
"Everyone has had
a teacher or professor who is incredibly knowledgeable about their
field, yet some of them are less-than-stellar teachers," he
continued. "One of the reasons for this is that teachers can be
unaware of what is going on in their students' heads, even though
they may have had exactly the same ideas when they were students
themselves. Knowledge of student misconceptions is a critical tool
for science teachers. It can help teachers to decide which
demonstration to do in class, and to start the lesson by asking
students to predict what's going to happen. If a teacher doesn't have
this special kind of knowledge, though, it's nearly impossible to
change students' ideas.
"The best
teachers base their lessons on what the American humorist-philosopher
Will Rogers observed: It ain't what they don't know that gives
them trouble, it's what they know that ain't so."
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