Doing Science at the Library: Chemistry in the Chambers

This post is coauthored by Kelsey Beeghly, the 2023-2024 Albert Einstein Distinguished Educator Fellow at the Library of Congress and Andrew Davis, a chemist in the Preservation and Research Testing Division. It is the second in a series focused on the science being done at the Library and engaging students in exploring the research methods used by the scientists. 

Chemical experimentation might not be the first thing that people think of when they hear “Library of Congress,” but without knowledge gained from ongoing tests happening within the Preservation and Research Testing Division, many of the collection items in storage and on display would perish because of the natural aging process. Chambers inside the aging lab allow scientists to conduct experiments to determine how factors like heat, humidity, and light affect specific types of materials, such as adhesives, paper, and multimedia discs. Students can explore these concepts by themselves for free through watching a video and carrying out experiments using only paper and sunlight. 

Before watching the video, ask students questions to elicit prior knowledge about chemical degradation processes. What happens if they leave clothes or papers out in the sun? What happens to old pots and pans that have been heated repeatedly in the oven? What causes materials to become faded or brittle over time? 

 Students can then look through a newspaper to select pictures, comics, or stories that they like, and they can guess how those materials will look after extended light exposure (mimicking display or exhibition). They can place these selections in direct sunlight, folded in half or in sections which will shade the interior of the folds, like in the example below. They might try normal newspaper compared to glossy ads. Students can also try placing paper under various protective layers, like aluminum foil, plastic sleeves, or even sunglasses, to see how those affect discoloration. Rapidly changing paper like solar paper can work for quicker experiments. 

Challenge students to design an experiment investigating the effects of heat or light on the paper they’re working with. Ask them how they will measure changes in color or strength of the paper and emphasize the importance of a control group for comparison. What patterns emerge between composition of paper and quality after testing? If the paper undergoing their test was of historical importance, what might students do with the information gathered from their experiment?   

The PRTD tests not only paper, but also adhesives. This video takes students to the aging lab for Andrew’s experiments testing the effects of heat, light, and humidity. After watching, ask students to analyze the results, pictured above, of an experiment in PRTD testing two types of adhesives. Which adhesive do you think was suggested to the conservators, and why?  

With these tests, Andrew and his co-workers identified repair adhesives which were most stable, which opened up new materials and methods that preservation staff can use with confidence to ensure continued access to the Library’s collection. Much of the underlying science for accelerated aging is still being actively researched, and Andrew continues to study it. Andrew studied chemistry in college, received his doctorate in polymer science, and has always had a large stack of books at his bedside table. He owes his love of chemistry to a high school teacher who encouraged curiosity and experimentation (shout out Mrs. Morse!) and greatly enjoys working with students.  

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