Here's a photo montage of the annual science festival held in Philadelphia on April 22nd. It is one of the key events in a full week of science festivities - more info can be found at the Philadelphia Science Festival home page.
Here's a photo montage of the annual science festival held in Philadelphia on April 22nd. It is one of the key events in a full week of science festivities - more info can be found at the Philadelphia Science Festival home page.