This week in science: The fluid dynamics of crowds, a bird fossil and morning mindsets
NPR's Ailsa Chang talks with Emily Kwong and Regina Barber of Short Wave about the fluid dynamics of crowds, an early fossil of a modern bird and new data on how people's moods change through the day.
![This week in science: The fluid dynamics of crowds, a bird fossil and morning mindsets](https://media.npr.org/include/images/facebook-default-wide-s1400-c100.jpg)
NPR's Ailsa Chang talks with Emily Kwong and Regina Barber of Short Wave about the fluid dynamics of crowds, an early fossil of a modern bird and new data on how people's moods change through the day.