Bugs' Bodies

Objectives of the Remodelled Plan

The students will:

       consider their preconceptions about insect anatomy while they build
models of insects 
       after learning more about insect anatomy, they will rebuild their
models to incorporate their new
       understanding thereby examining, evaluating and modifying their
assumptions 

Standard Approach

In a brief discussion of insects, texts introduce the structures common to
all insects. They name the three main
parts of the body and give the number of legs, eyes, antennae.

Critique

Such brief text passages present some simple information about the
structure of insects. They give us an
opportunity to discuss techniques of science teaching which recognize that
students have preconceptions about
the subjects we teach. It is important to remember that our students often
have ideas about the subjects we are
teaching. Students at this level will usually have some preconceptions
about insects. They have ideas about what
insects are and are not (most will not identify insects as animals), what
they do, how they are built. Here are
some important points to consider:

       Children do not come into our classes as "blank slates" ready to
receive instruction. Rather, they often
       have well-developed, but somewhat incorrect, concepts already.
These preconceptions strongly affect the
       understanding children come to when they learn science in school. 
       Children's preconceptions are often interesting and creative ways
to make sense of the various things
       children have themselves observed or have been told in or out of
school. Children's preconceptions are not
       "learned" as a single idea, but are constructed in the child's mind
as he or she actively tries to make sense
       of many experiences and pieces of information from both schooling
and out-of-school experiences. 
       Since these preconceptions often do "make sense" to some degree,
especially in the child's viewpoint, it
       is difficult to change them. Often we as teachers think, "I said it
clearly and correctly. Why didn't they get
       it?" We forget that children's' preconceptions are very resistant
to change, and we often need to take an
       approach designed to help children modify the pre-conceptions they
have already constructed. 

Since children do come into our classes with their own preconceptions, how
can we best teach science so that
students form a more accurate and complete understanding of things? In
teaching science concepts, we need to
adopt a style of teaching somewhat different than we might use for other
subject matter. The principles of
effective didactic instruction, while sometimes useful when we are
teaching information or well-defined skills,
aren't the ticket here, because this particular model of instruction
doesn't address two necessary features of good
science teaching. In science teaching, we must first take into account
students' prior knowledge and, second, we
must shape instruction so that the students consider what they already
know and then become actively involved in
modifying their understanding to make it more complete and accurate. 

In the lesson on bugs or any other science lesson, we should stress the
connection between what the children are
learning in school and their everyday experience. There are at least two
important reasons for doing this. First, we
all hope that school learning can help children understand their everyday
lives; this should be one of the main goals
of schooling. Often we try to use this connection to motivate our students
to learn. But there is another reason to
help students realize that they already have ideas about the science
topics they are studying, and this idea is
closely related to our discussion of students' preconceptions. Too often
students seemingly compartmentalize
their ideas into "school ideas" and "ideas about real life." In order for
school science to help students make their
views of the world more accurate and complete, we must break down the
division between school ideas and real
life ideas. Since much of good science instruction involves helping
students refine their preconceptions, it is very
important to set up situations which encourage students to look in their
"real life compartment" for their existing
ideas on the topics they are studying.

Strategies Used to Remodel

       S-1 thinking independently 
       S-30 examining or evaluating assumptions 

Remodelled Lesson Plan

Let's look at a lesson on bugs to understand how these ideas might work.
While no single example can provide a
complete illustration, this lesson on "How Bugs' Bodies Are Built" will
give us an example. We should start our
lesson with an activity designed to help the students recognize that they
already have some ideas on bugs' bodies.
While it might work just to have a discussion, there are better ways. In
the case of our lesson on bugs, we could
begin by having the students build models of bugs in "Mr. Potatohead"
fashion. S-1 In doing this, they must
recognize and act on their preconceptions about how bugs' bodies are
built. For instance, many students might
think that bugs have eight legs, and their models would represent this.

After the class built their models (maybe even working in groups in order
to share their individual preconceptions
socially), the teacher would provide some information about bugs. This
could take place in any number of ways,
including all the traditional methods of instruction. The "principles of
effective didactic instruction" provide helpful
ideas for organizing these kinds of informational presentations. Then,
following this direct instruction, the students
would go back to their bug models, discuss with each other how real bugs
differed from their model bugs and
perhaps make a new version or modify the old one. By going back to the
original model to make corrections, the
students will confront their old ideas about bugs. In this active way,
their preconceptions about how bugs bodies
are built will be changed to be more accurate. S-30