The Newton Free Library seeks additional exhibitors for its fourth annual STEAM Expo, on July 15, Noon-3PM. (Exhibitors should arrive 9:30-11AM.) At the STEAM Expo, attendees experience the work of scientists and engineers through opportunities to explore, experiment, design and invent. Exhibitors should target hands-on activities and demonstrations that would appeal to all ages. Here’s who exhibited last year. For consideration this year, apply online by May 28.