Creating Benchmarks For Science Education
Andrew Ahlgren
Project 2061
Progression of understanding maps were one important tool in
coordinating the research and information needed for creating K-12 science
standards.
Project 2061 has been constructing goals for science, mathematics, and
technology education since 1985. During our first three years of work. we
recommended what students should remember by the time they leave high school
(Science for All Americans1989). Since 1988, we've been working on
reasonable expectations for students at earlier grade levels (Benchmarks
for Science Literacy, in draft). This new volume will include benchmark
lists, some of our progression-of-understanding maps, and essays related to
the benchmark topics.
We intend the benchmarks to be used by school districts or curriculum developers
in constructing alternative K- 12 curriculum models adapted to their own populations
and circumstances. Before we reach that point, though, we believe some reflection
on how we created the benchmarks can be a stimulus to other curriculum reform
efforts.
The experience of writing benchmarks is highly stimulating. But make no mistake
about it: The work is difficult, and getting started seems to discourage many
people from the undertaking. Still the quality of thinking and conversation
that goes on is often impressive, even when the tentative product may not
be.
Benchmark Grades
The National Assessment of Educational Progress (NAEP) has popularized grades
4 and 8 as benchmark grades, and the National Council of Teachers of Mathematics
(NCTM) has followed that pattern (Curriculum and Evaluation Standards for
School Mathematics 1989). However, the district teams working with Project
2061 decided that the psychological distance from K to 8 requires more than
a single benchmark. The end of grades 2 and 5 were recommended as being more
meaningful developmental breaks, and we are designing benchmarks for those
grades.
It is not our intention that 2nd graders should be subjected to formal, national
examinations on their progress in science (as seems to be in the cards for
older children). The feel of the expectations for grade 2 is distinctly different
from that for grade 5, so we believe it is important to discourage kindergarten
teachers from embarking immediately toward grade 5 goals. By their modest,
nontechnical nature, grade 2 benchmarks suggest what students cannot be counted
on to know as they begin grade 3, and this may temper expectations for what
children can learn in grades 3 through 5.
Inferring Benchmarks
In crafting the lower-glade expectations. we drew partly on an analysis of
what ideas would be needed to achieve the 12th-grade understandings in Science
for All Americans. We also considered estimates of what students are capable
of at different ages, drawing information from the experienced teachers on
our district teams and from researchers who study how children understand
and learn science. Unfortunately, the availability of published research on
children s understanding of science is very uneven over different content
areas.
We have found that it is seldom possible to work backward from 12th grade goals
one at a time to create a neat stack of previous levels of sophistication.
Usually there are convergences (several ideas required to understand a subsequent
idea) and divergences (several ideas depending on one prior idea). The natural
medium to express such goals is therefore a diagram with boxes and arrows.
We called our speculative charting a progression-of-understanding map (to
distinguish it from the concept map currently popular in science education).
Figure 1 is an example of a draft of a progression-of-understanding map, depicting
ideas related to a section on the structure of matter (Science for All
Americans Chapter 4: The Physical Setting). Reading from bottom to top,
the map shows a rough progression in time, beginning from notions students
hold when they enter school. When we sketched this map, the sequence of ideas
was more important than tying ideas to any particular grade. Estimation of
approximate grade placement for each idea usually came later.
Unfortunately, the availability of published research on children's understanding
of science is very uneven over different content areas. The toughest part
of the map was in the middle. Without the firm guidance of research on many
topics, we were in the same place as the Geography Task Force of the National
Council on Education Standards and Testing when they wrote: "It was difficult
to set 8th grade standards, other than indicating that students should be
expected to know more than they did in the 4th grade and less than the 12th
grade" (Raising Standards for American Education 1992, p. L-4).
Compounding our uncertainty was the possible difference between what children
could be expected to do now, with their current history in the school system,
and what 5th or 8th graders eventually might be able to do if they had optimal
experiences.
When we began mapping, we intended to cover one conceptual strand at a time,
leaving some loose ends that would later connect to other strands. For example,
the structure of matter shows obvious connections to the flow of matter and
energy. The structure of matter was a whole section in Science for All Americans,
and perhaps it was too large a conceptual chunk to represent comfortably on
a single map. (Notice that it is incomplete in fig. 1.) It soon became evident
that a progression of understanding map for a single strand was already more
complex than most people would find inviting.
Software support for constructing each map and for making connections among
them would be very helpful (and we now have a grant to develop such software).
We intend to create a curriculum resource data base that will link appropriate
parts of the progression-of-understanding maps, giving users the option of
choosing the complexity of information they want to consider. The resource
base would also link benchmarks to blocks, to activities and materials, and
to appropriate assessment suggestions.
We plan to accompany benchmark lists with essays that will call attention to
the progressions of various strands and connections among them. For example,
the essay accompanying the benchmarks for the structure of matter would draw
attention to the parallel development of four different strands: properties
of substances, combinations of parts, invisibly small pieces, and conservation
of matter.
Essays, which are being prepared by our teams and staff, will also draw on
the available educational and psychological research, calling attention to
difficulties that students are likely to have at each level and, in particular,
to persistent previous conceptions that may interfere with learning (see fig.
2). We are still uncertain about how far essays should go beyond suggesting
appropriate kinds of instruction. (The research has much less to say about
instruction to overcome difficulties than about the difficulties themselves.)
Figure 2
Literacy Goal: The Structure of Matter
| The following example of an essay and benchmark list is taken from
the draft of Benchmarks for Science Literacy (in draft). |
Students will learn about the nature of atoms and molecules and
the structure of matter.
Of all sections, this one may have the most implications for students
eventual understanding of the picture that science paints of how
the world works. However, it may also offer the most difficulties.
The theory of atoms and molecules is powerful in explaining our
world, but it requires bringing together a number of lines of
evidence and imagination: about the properties of materials and
their combinations, changes of state, effects of temperature,
behavior of large collections of pieces, the construction of objects
from parts- even about the desirability of simplicity in explanation.
All of these should be grasped by children during middle school,
so that the unifying ideas of atoms can be developed by the end
of grade 8.
The scientific understanding of atoms and molecules requires students
to entertain the notion that all visible things are composed of
invisible particles. Another notion is that everything might be
made up of a relatively few ingredients. An idea preliminary to
this is that materials combined in different ways can have different
properties. And still preliminary to that is the very notion of
properties of materials.
Parallel to consideration of properties of combinations is the
notion that the bulk properties of materials can be very different
from the properties of their minute parts-an idea counter to the
students intuition.1 And parallel too is the idea of
an unchanging total amount of matter, beginning with the evidence
that total weight stays the same during all sorts of changes in
materials.2
Grades 3 through 5
The study of materials should continue throughout these years but
become more systematic and quantitative. Students should design
and build things that put different requirements on the properties
of materials. They should be expected to write clear descriptions
of their designs and experiments, present their findings whenever
possible in tables and graphs (designed by the students, not the
teacher) and enter their data and results in a computer database.
Students should measure (weight, dimensions. temperature), estimate
(dimensions, weight, population size), and calculate (area, volume,
population size) using hand-held calculators when necessary.3
With magnifiers, they should inspect substances composed of large
collections of particles-sand, spices. powders-to discover the
unexpected details at smaller scales. They should observe and
describe the (sometimes solid-like, sometimes liquid-like) behavior
of large populations of pieces-powders, marbles, sugar cubes,
or wooden blocks.
By the end of the 5th grade, students should know that
- Heating and cooling cause changes in the properties
of materials. Many kinds of changes occur faster under hotter
conditions.
- However parts are assembled, the weight of the thing made
is always the same as the sum of the parts; and when a thing
is broken into parts, the parts together weighed the same
as the original thing.
- Materials may be composed of parts that are too small to
be seen without magnification.
- When a new material is made by combining two or more other
materials, it can have properties that are different from
any of them. For that reason, a lot of different kinds of
materials can be made from a small number of basic kinds.
- A collection of a large number of pieces may keep its shape
or flow like a liquid, depending on how the pieces stick together
or how they are stacked.
1Brook
et al 1984, Driver 1987.
2At the beginning, children have various ideas about
what is matter For many, gases and even liquids are not seen as
having weight or as being matter (Lee et al In press, Driver 1987,
Stavy 1990). very tiny solid particles are also not seen as having
weight-because their weight cannot be felt (Smith, Carey, and
Wiser 1985, Carey 1991).
3Research shows that children may consider anything
so light that they cannot feel its weight to have no weight at
all (Smith. Carey, and Wiser 1985; Carey 1991) Lots of weighing
on increasingly sensitive balances, including weighing piles of
small things and dividing them to find the weight of each, will
help. |
Benchmark Adjustments
Once in the thick of producing benchmarks, occasions will arise when a benchmark
statement doesn't t seem well suited to its designated grade level. The easiest
option is to move the benchmark intact to another grade level, making adjustments
to any benchmarks connected to it.
A second option is to rewrite the statement at a level of sophistication more
appropriate to the current grade level, but this is more than a stylistic
transformation. Grade adjustments can seldom be made so simply as changing
the vocabulary. Rewriting usually requires rethinking what students should
be able to do-in their heads or behaviorally-at that level.
A third rewriting option is the most difficult but probably the most fruitful:
tease apart the substance of the benchmark and create two new ones, keeping
one at the current level and putting the other at a different one. Again,
merely making style changes in language won't change the substance of the
benchmark. One must reconsider what students could understand and what the
likely sequence of understanding is.
Knowledge vs. Belief
Research shows that children may understand a scientific explanation of phenomena
before they believe it (for example, Hewson and Hewson 1992, Osborne and Freyberg
1985). The longer the time gap between being able to state an idea and eventually
believing it, the greater the problem for writing benchmarks. Should a benchmark
about children's ability to explain something specify that they can produce
a scientific explanation, or should we try to require their acceptance of
it as well?
From a philosophical point of view, Project 2061 would prefer to require knowledge
rather than belief. A similar dilemma appeared in writing the Values and Attitudes
section in Science for All Americans. We rejected the goal that everyone
should like science, mathematics, and technology or should believe these endeavors
are of net benefit to humankind. We agreed instead on the goal that students
attitudes-whether they turn out to be positive, negative, or neutral-should
be based on a sound understanding.
A poignant case might be that of evolution through natural selection. We can
reasonably require that students understand what the scientific theory is,
but do not have to require students to believe that is how present life on
earth necessarily came to be.
Final Thoughts
Benchmark drafts should be tried out with a variety of readers, not just for
approval or minor editing, but to see how they are likely to be interpreted
and used. Writing good benchmarks may not require setting fixed rules as much
as it requires being continually vigilant about how one's intent might be
misunderstood.
Researcher Pat Heller (of the University of Minnesota) summarized the task
for us after a recent writing retreat:
- Make benchmarks not so specific as to be limiting and not so general that
no one is quite sure what you re talking about.
- Have a clear sequence where necessary within a grade level.
- Have a progression from one grade level to the next that illustrates increasing
sophistication.
- Show connections between benchmarks under different goals.
- Write them to be developmentally appropriate, assessable, and relevant
to the child's world.
REFERENCES
Hewson, P., and M. Hewson. (1992). "The Status of Students' Conceptions."
In Research in Physics Learning: Theoretical Issues and Empirical Studies
edited by R. Duit, F. Goldberg, and H. Niedderer. Kiel, Germany: Institute
for Science Education.
Osborne, R., and P. Freyberg. (1985). "Roles for the Science Teacher."
In Learning in Sciences edited by R. Osborne and P. Freyberg. Auckland:
Heinemann.
Raising Standards for American Education. (January 24, 1992). Washington,
D.C.: National Council on Education Standards and Testing.
Science for all Americans. ( 1989). Washington, D.C.: American Association
for the Advancement Of Science.
Ahlgren, A. 1993. Creating Benchmarks For Science Education. Educational
Leadership, 50 (5).
