Behind the Cover: February 2023

Each month, Physics Today editors explore the research and design choices that inspired the latest cover of the magazine.

The constriction may be microscopic, like the pores of a filter, or macroscopic, like the narrow road that produced the traffic jam in Kuala Lumpur, Malaysia, shown on this month’s cover. Either way, the phenomenon occurs in countless environments and on numerous scales. Engineering, scientific, social, and medical problems abound as a result of clogging.

The authors of the magazine’s feature article on the subject address how various clogs happen and how to mitigate them. For example, “Emergency exits can become a bottleneck if too many people try to pass through at once,” they write. The same is true of automobiles moving along a curving, pedestrian-heavy highway.

The colorful scene on the cover captures the claustrophobic character of such flows through confined geometries. Surprisingly, though, the photograph wasn’t the first cover choice for Physics Today‘s art director, Donna Padian. When she was mulling over different images, she originally found a pond crowded with water lilies most appealing. She savored the chance to showcase one of Claude Monet’s famous paintings of the flowers in Giverny. But the traffic jam was favored by the editors and eventually won the day.

As for the cover text, “I tried to ‘jam’ the main cover line into the traffic,” Padian says, “and needed bright red type with bright yellow background for readability and emphasis.” The narrow Niagara typeface further emphasizes the crowdedness of the photograph.