Metric Measurements, Magnitudes, and Mathematics Matter in the Science of Scale


Why should we care about “big ideas” (i.e. NGSS Crosscutting Concepts)?

From the earliest wonderings of ancient Greek natural philosophers to the most recent cutting-edge STEM research, scientists have been concerned about both the forests and the trees. Isolating, identifying, and investigating individual concepts (or trees) has repeatedly led scientists to discover both more broadly applicable theories and overarching themes (or forests). Scientists have always sought to discover—and science teachers have always aimed to help their students uncover—the unity and underlying order or cosmos in a universe that displays such seemingly chaotic diversity. Perhaps it is this sense of cosmos that led you to become a science teacher!

Unfortunately, traditional “two-by-four” teaching all too often limits student experiences to what they find between the two covers of their textbook and within the four walls of the classroom. The tyranny of terminology and tests drives students to short-term memorization of names and factoids about trees—often at the expense of missing the lasting power and beauty of the forest. Sadly, many students never experience the wonderful consilience of knowledge within and across the “useful fiction” of disciplinary boundaries. Participating in a webinar I’ll be hosting next Monday can help raise your awareness about this issue and translate your concerns into concrete, make-a-difference-on-Monday type actions with your students.

What educational resources can help me identify and investigate the “big ideas” of science?

The AAAS Benchmarks (1996), the National Research Council’s National Science Education Standards (1996), the Framework for Science Education (2012), and the Next Generation Science Standards (2013) respectively identify four common themes, five unifying concepts, and seven crosscutting concepts that serve as the overarching framework (or forest) for all science concepts. While the number of “big ideas” depends on whether one is a lumper or splitter, all four documents are good reads and all identified scale as a key, big-picture idea. The webinar will offer examples of and additional educational resources for incorporating this iconic “big idea” within and across grade levels and scientific disciplines.

If scale is such a big deal, then surely it must be correctly represented in textbooks?

Immense, “powers of 10” scales frame nearly every aspect of our universe including:
size/distance (for example: sub-, subatomic particles to the furthest regions of the known universe)
time (for example: microseconds to a timeline that reaches back to the Big Bang)
speed (for example: slow pace of evolution to the speed of light)

Humans rely heavily on visual information and only in the briefest microsecond of our evolutionary history have we developed the ability to write and read. So, the adage that a “picture is worth a 1,000 words” is certainly true. Yet visualizing scales that extend far beyond the range of human senses and our limited lifespans is both a philosophical and pedagogical problem. Intelligent Curriculum-Instruction-Assessment is designed to develop visual intelligence, critical thinking, and the appropriate sense of awe and wonder about the universe.

Pre-NGSS textbooks visuals typically misrepresent the crosscutting concept of scale by committing either:

sins of omission: Actual photographic images are displayed without any information about the scale. For example, based on textbook visual “lies,” students may assume that rod-shaped bacteria and paramecium are about the same size.

sins of commission: Visual models are used and misrepresent the relative scale of different objects or timelines. For example, every textbook-size image of our solar system or the atom leads to major underestimations of the relative sizes and immense distances between the component parts of the systems. Truncated scales for evolutionary history and the electromagnetic scales are similarly problematic.

While new NGSS-aligned textbooks can avoid some “sins of scale” with appropriate labeling, the restriction on the size of physical textbooks mandates that many lies can only be corrected outside the book with the use of models that use the dimensions of a classroom, school hallway, school district, or even larger physical spaces and/or the use of scale computer animations and simulations. In my webinar, you will directly experience several such models.

The views expressed in this article are those of the author and do not necessarily represent those of HMH.


Dr. Thomas O’Brien hosted a webinar, Metric Measurements, Magnitudes, and Mathematics Matter in the Science of Scale, on Monday, May 21 at 7 p.m. Eastern Time. Watch the recording here.

*Next Generation Science Standards and logo are registered trademarks of Achieve. Neither Achieve nor the lead states and partners that developed the Next Generation Science Standards was involved in the production of, and does not endorse, this product.

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