What do large crowds of people and water have in common? They both act like fluids. When crowds cheer, sway and clump together, the movements look like ripples of water. Researchers hope insights from physics like this one could help officials and engineers create safer crowds at festivals.Help shape the future of Short Wave by taking our survey: npr.org/shortwavesurveyListen to every episode of Short Wave sponsor-free and support our work at NPR by signing up for Short Wave+ at plus.npr.org/shortwave.Learn more about sponsor message choices: podcastchoices.com/adchoicesNPR Privacy Policy