From Wikipedia, the free encyclopedia Dianna Leilani Cowern (born May 4, 1989) is a science communicator. She is a YouTuber who uploads videos explaining various physical phenomena to the PBS Digital Studios channel Physics Girl.[3] She has also often collaborated with other STEM-based YouTube personalities, including fellow science communicator Derek Muller of the channel Veritasium, maker Simone Giertz, and mathematics animator Grant Sanderson of 3Blue1Brown.