Primary Sources in Science Classrooms: Size, Scale, and Scientific Communication

This post was written by Trey Smith, the Library of Congress 2015-16 Science Teacher in Residence.

From atoms to cells, organisms to ecosystems, and Earth’s systems to galaxies, scientists study and make sense of objects and phenomena of all shapes and sizes. Primary sources can serve as starting points for students to explore the ways in which scientists study and communicate about things and events, large and small.

Introduce concepts related to size, scale, and scientific communication with items from the Library’s new primary source set on Scientific Data: Observing, Recording, and Communicating Information. (There is also a new interactive ebook version of this set.)

Texts in the set include:

• descriptions from Aristarchus about the positions of the Earth, moon, and Sun;
• drawings by Robert Hooke of cells as he saw them with a microscope;
• comparisons made by John Dalton of the relative sizes of atoms and molecules;
• diagrams by Sir Isaac Newton about the behavior of light; and
• data tables assembled by Ellen H. Swallow Richards detailing the pollution of water systems over time.

Ask students to order the texts according to the sizes of the objects and phenomena featured. After students discuss and agree upon relative sizes, facilitate analysis of each item using the Library’s Primary Source Analysis Tool:

• What tools might a scientist have needed to study the object or phenomenon shown?
• What clues, if any, does each document provide about size and scale?

Next, provide each student with bibliographic information about an item in the set. Support students in consulting secondary sources about the author and history of the scientific ideas in their document. Students might uncover stories about new ways of seeing—in terms of both tools and paradigms—and scientifically describing phenomena. Create opportunities for students to share and compare their findings.

Facilitate further student investigations:

• What tools and methods do scientists use today to study things large or small?
• What are the actual sizes—in terms of distance, mass, or time—of the things or events shown in each primary source? And across each document, how do these sizes compare?

  

Scientific texts often make visible objects and phenomena that are otherwise difficult to see or understand. Each item in this set is a two-dimensional model that may simultaneously reveal and disguise differences in size, speed, and proportion. Compare the geological map of the U.S. showing rock layers that formed over hundreds of millions of years with Eadweard Muybridge’s photographs of animal motion captured at fractions of a second. Both documents can be held in human hands but depict changes over time that cannot be directly observed by humans.

• How do scientific models convey senses of time?
• What misconceptions about time might scientific documents reinforce?
• What other kinds of models do scientists create? Why are other models useful?

Beyond the dimensions of the objects and phenomena depicted, there is something powerful about studying scientific texts that have historical significance and that reveal how human thinking has changed over time.

What other scientific primary sources, both historical and modern, might students explore alongside the items in this set?