Scale is a unifying concept in science. Whether one is considering the size and scope of the universe, an atom, or anything in-between, conceptual understanding of scale is a prerequisite to understanding. Other phenomena requiring knowledge of scale include geologic time, pH, and maps. Cognitively, most middle school students hold a concrete, incomplete conception of scale. Teachers can facilitate conceptual change to a more abstract conception with help from these resources.

Secret Worlds: The Universe Within
View the Milky Way at 10 million light years from the Earth. Then move through space toward the Earth in successive orders of magnitude until you reach leaf cells, the cell nucleus, chromatin, DNA, and finally the subatomic universe of electrons and protons. You can control the speed at which the images are flashed automatically or manually.

Powers of 10
This brief webcast approaches scale from the opposite direction of the tutorial above — moving from a picnic in a park to outer space and back to human cells — and indicates when the scale has changed by a magnitude of 10X.

Table of Images from Wordwizz.com
Bruce Bryson is the author of this award-winning site. It provides a table of contents in which teachers will find images of interest, such as the solar system, a bee’s eye, and the atomic nucleus. You may decide to have pairs of students investigate one item from the list and then share their findings in order of magnitude with the rest of the class.

Earthquake Scale and Magnitude
Not all scales are in powers of 10, as can be seen at this site.

Weather – Wind Chill
This interactive site explains how wind chill is estimated and allows students to calculate it. In doing so, students see a different manifestation of scale and magnitudes involving the interaction of variables, rather than a one-to-one corresponding change as in powers of 10.

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