Kids who are hospitalized for long periods by trauma or chronic illness risk falling behind in school. Now robots are here to help. PEBBLES (Providing Education by Bringing Learning Environments to Students) have rolled into five U.S. pediatric centers --in Cleveland, Ohio; Baltimore, Md.; New Haven, Conn.; Miami; and Chicago. The robots, created by Toronto-based Telbotics, work in pairs. One with a 15-in. LCD screen for a face goes to school in the absent child's place. The other remains in the hospital, transmitting an image of the child's face to the classroom. Using a video-game-style controller, the child can direct the school robot to raise its hand to ask a question or swivel its head to follow the teacher. Scanning and printing features allow the child to receive and hand in homework assignments. The pilot project is still being refined. Next step, the creators say, is a robot that can go into the halls too, so that the ailing student can chat with friends between classes.