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Primary Source Set Weather Forecasting

The resources in this primary source set are intended for classroom use. If your use will be beyond a single classroom, please review the copyright and fair use guidelines.

Teacher’s Guide

To help your students analyze these primary sources, get a graphic organizer and guides: Analysis Tool and Guides

Weather affects everything in our lives, including the ability to grow food, travel to see loved ones, or remain safe. Therefore, people have always looked for patterns in the weather, hoping to make accurate forecasts.

Background

A Search for Weather Patterns

As early as 650 B.C., ancient civilizations made observations of the world around them and looked for patterns in the changing of the seasons, in clouds and in the stars, hoping to forecast future weather events. From such observations, weather lore was developed. Thus, a “red sky at night” would lead to fair weather and “sailor’s delight,” whereas “red sky at morning” portended bad weather, for a “sailor’s warning.” For centuries, people have made causal connections between observable phenomena and future weather events, and some weather lore persists today.

Ambient Data Collection and Recording

Collecting quantifiable weather measurements, such as temperature or air pressure, can also reveal patterns for weather prediction. From the 15th to the 18th centuries in Europe, a number of now well-known weather instruments were developed for just this purpose. These include the thermometer (temperature), the barometer (air pressure), the anemometer (wind speed), and the hygrometer (humidity).

Thomas Jefferson became a pioneer in weather data collection and recording in the United States in the mid to late 18th century. He faithfully collected weather data twice daily at his home in Monticello and encouraged his friends to do the same, following his precise timing and format in their locations. Jefferson believed that, if people throughout the country simultaneously collected weather data, they could create a global picture of meteorological conditions. He was also keenly interested in how his weather records could aid society. Using a combination of his measurements, along with anecdotal observations from “the elderly,” (Jefferson’s phrase) he speculated that over the years Virginia had undergone steady “climate change” that was affecting its agriculture, though it should be noted that this claim was hotly debated at the time.

Real-Time Sharing of Weather Data

The invention of the telegraph in 1835 and the subsequent emergence of telegraph networks revolutionized weather forecasting. The ability to communicate data and observations in real time over great distances allowed for the creation of weather maps over large geographical areas, so that patterns could be studied on a greater scale. It also enabled timely communications of weather events such as storm systems to help save lives and property. With the emergence of telegraph networks, weather observation stations began popping up all over the globe. In 1870, the United States National Weather Service was officially formed as part of the U.S. Army Signal Corps, cementing the importance of weather prediction as a U.S. national priority.

Advances in Engineering, Technology and Mathematics

Over time, engineering enhancements and innovations have enabled weather forecasting to become more accurate. For example, people had attached weather instruments to hot air balloons and kites to collect data in the upper atmosphere since the late 18th century. By the early 1900s, manned aircraft were used as well. But until the radiosonde was invented in the 1920s, no one method could simultaneously travel to high altitudes, operate in all kinds of weather, and provide real-time data to individuals on the ground. The radiosonde was a lightweight box equipped with weather instruments and a radio transmitter, carried high into the atmosphere in an unmanned balloon, which could travel to great heights and in inclement weather. Although the balloons would eventually burst, while they were rising weather measurements could be transmitted real-time to a ground station for analysis. Today, we use weather satellites in space and hurricane hunter aircraft that fly through the eye of storms to collect weather data.

The 20th century also saw the emergence of the notion that weather forecasts could be made with the help of mathematics and computers, by feeding data into equations, solving them, and creating weather models. Today, meteorologists continue to develop new tools and methods to make predictions more accurate. But while the details evolve, some basic tenets remain the same: an ongoing search for weather patterns to predict what will happen in the future seeks to help communities prepare and keep people safe.

Suggestions for Teachers

Using The Children’s Object Book, younger students might investigate a season represented in the book. Take students outdoors to compare what they see in their own world to how the season is represented in the book. Brainstorm a list of items they connect with the season, and then compare it to the images. Challenge students to differentiate between characteristics of weather in a season and how they react to that weather. For example, the weather in winter may be cold. Students may react to the weather by wearing a coat, hat, and gloves.

Invite students to examine a weather instrument represented in the set. Ask them what it is meant to measure and how it measures. Challenge students to explore structure and function by recreating the weather instrument and testing it outdoors as part of an interactive engineering project. Ask students: Does the student-created instrument measure weather data in the same way as the illustrated instrument? Does the student design offer any improvements?

Guide students through a paired analysis of Thomas Jefferson’s weather data tables and George Washington’s weather diary. How does each represent data? Students can collect weather data in the same way Jefferson and Washington did and use the data to look for patterns over time. Ask students: Why would one method be preferred over the other? What insights into purpose and benefits does this comparison provide? What evidence from the analysis and your own weather data collection supports your ideas?

Several primary sources in the set address why recognizing weather patterns and predicting the weather is important. Ask students to create a list of reasons weather prediction has been important based on selections from the primary source set. What reasons would students add from personal experience?

Additional Resources

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