The physics of fluids explains how crowds of marathon runners move
A new liquid-inspired theory can predict the jostling of throngs of marathoners lining up to race
![marathon finish line](https://i0.wp.com/www.sciencenews.org/wp-content/uploads/2019/01/010219_EC_liquid-marathon_feat.jpg?fit=860%2C460&ssl=1)
SMOOTH MOVE Packs of runners in the Chicago Marathon behave like a liquid in the lead-up to the race, a new study finds.
N. Bain, D. Bartolo