Reflections Of Scale

One of my favorite intermittent treats at a gargantuan meeting like a national meeting of the American Chemical Society is when a presenter shares some innovative metaphor for describing a phenomenon whose more technical descriptions involve units or scales that are otherwise difficult to comprehend. Within an hour of arriving at the technical sessions today, I was lucky to receive two such treats. The first was in a session in the Division of Analytical Chemistry titled “The Secret Lives of Trace Volatiles.” Kevin Goodner of the natural extract firm Sensus, in Hamilton, Ohio, in his talk titled “The butterfly effect in food and flavor research,” turned to football fields as a way of describing the astounding apparentness of specific aroma chemicals. One single drop of the grapefruit chemical, p-methene-8-thiol, for example, would be apparent in a football-field sized pool of water that was 350 feet deep, Goodner told a full room in the Renaissance Washington Hotel. He then used various depths of this vast imaginary pool as a unit of comparison for other volatiles that came up in his talk. For example, the 100-200 part-per-trillion presence of beta-demascenone in orange juice is equivalent to about one drop of the volatile chemical in a 15-foot deep football-field-sized pool. Despite their trace presence, “these are trace compounds that have effects,” Goodner noted, reiterating the point of his talk. About an hour later and a block north, in the Walter E. Washington Convention Center, during the Presidential Plenary Symposium on Chemistry and Global Security: Challenges and Opportunities, Vahid Majidi took a non-chemical phenomenon and put it in terms familiar to analytical chemists. Majidi, Assistant Director of the FBI’s Weapons of Mass Destruction Directorate, described the challenge of finding one bad human actor in the global sea of humanity, about 6.68 billion people, as a part-per-billion analytical challenge. This was an instantly graspable way of thinking in terms of billionths. I would guess that at any particular moment at the meeting, dozens of presenters are sharing equally engaging snippets of quantitative communication with their audiences. When you run into them at the meeting or elsewhere in the scientific landscape, share them with your fellow C&ENtral Science blog watchers.

Author: Ivan Amato

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