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Analyzing Historical Weather Tools to Understand Core Scientific Concepts

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The following is a guest post by Michael Apfeldorf of the Library of Congress.

The new Weather Forecasting Primary Source Set from the Library of Congress includes depictions of a number of early weather tools. Analyzing these historical primary sources depicting technological innovations can offer students insights into the nature of science and science practices, as well as core scientific concepts.

Page in Lezioni accademiche; with early barometer created by Torricelli, 1715
Page in Lezioni accademiche, with early barometer created by Torricelli, 1715

Consider Evangelista Torricelli’s diagram of a barometer, widely believed to be the first. After first ensuring that students have requisite background knowledge about gases–that they take up space, have mass, and exert pressure–show them Torricelli’s diagram and ask key questions to support an inquiry analysis.

  • Based on what you know about gases, what do you think this tool measures?
  • How do you think the tool works?

Ask students to cite evidence from the drawing or from their background knowledge to support their hypotheses.

Students can use the Library’s Primary Source Analysis Tool to record the process of making observations, drawing inferences from those observations, and formulating questions for further investigation. Analyzing historical scientific drawings can provide rich opportunities to wrestle with core concepts.

For instance, Torricelli’s drawing shows two tubes that have been filled with a fluid, inverted, and placed within a container of the same fluid. Depending on the force of the air pressing down on the fluid in the container, the heights of the fluid in the tubes will vary. In order to determine how the tool works, students must look at the diagram and imagine air physically pushing the fluid throughout the system. Encourage students to annotate Torricelli’s diagram with their own understanding of air and pressure.

Later, as you reflect on the diagram with your students, it may be interesting to note that Torricelli wasn’t simply taking an established understanding of air pressure and designing a tool to measure it. Instead, he conducted an experiment and learned about air pressure as a consequence. At the time, most scientists thought that a vacuum above a column of fluid would draw up the liquid. In his experiment, Torricelli compared two tubes with different vacuums at the top, but found that the fluid height remained the same, leading to new insights about air pressure.

Finally, challenge students to design and build their own barometers. First, return to the diagram and ask additional questions, such as:

  • What components does the tool have? How are they put together?
  • What aspects of air and air pressure did it make use of?

After students have reviewed their understanding of air pressure and how a barometer works, encourage them to design and construct a barometer of their own.

barometer 1 barometer 2
 Two of the many ways that students can build a tool to measure air pressure.

There are many other historical weather tools included in this Primary Source Set, including an anemometer, snow gauge, weather balloons and kites, and several instruments at a National Weather Bureau kiosk. Similar analysis and investigations could be accomplished with any of these primary source documents.

Let us know in the comments what your students discovered!



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