There will be animals visiting from the Philadelphia Zoo, an explanation of the physics of the curve ball, and exhibits about insects, fossils, and mummies.
And the actual baseball game, starting at 1:05 p.m.
But before humans take the field, PhillieBot will have its moment.
The idea to build a robot pitcher came from Gerri Trooskin, director of the city science festival, which began Friday and runs through April 28. She pitched her proposal to the people at Penn's General Robotics, Automation, Sensing and Perception (GRASP) Laboratory, who were glad to oblige.
On Monday, after a month and a half of assembling parts and writing software in their spare time, Penn engineers Jordan Brindza and Jamie Gewirtz guided PhillieBot out to the mound for a final test.
At the touch of a button, the robot's silvery jointed arm reared back and then moved steadily toward home plate. At the top of its delivery - somewhat sooner than a human pitcher would do - the robot shot the ball homeward with a flick of its mechanical wrist.
The ball appeared to be traveling no more than 30 or 40 miles an hour, but that was by design. More accustomed to pitchers of the human variety, the Phillies organization, to ensure safety, did not want anything approaching the speeds of Halladay and his rotation mates.
Members of the team's grounds crew, busy tending the lush green field, eyed the electronic intruder with apparent skepticism.
But all had been cleared in advance with head groundskeeper Mike Boekholder, who was assured that PhillieBot would not tear up his playing surface.
"It's an interesting deal," Boekholder said of the robot pitcher.
You might think PhillieBot does the same thing as those machines that spit out baseballs at batting cages. But that'd be like describing Le Bec-Fin as a place to grab a snack.
