The Medfield Public Library is hosting “Mad Science: Invention-ation” Thursday from 3:30 to 4:30 p.m. Participants ages 5 to 10 will learn about machines through hands-on activities, and will make machines of their own. Each child will also be able to take home an inventor’s notebook. The program will be held in the meeting room, and registration is required. For more information or to register, visit www.medfieldlibrary.org.