Now that the fall semester is over at UC Berkeley, the town is emptier and quieter. But up in the hills, at the Lawrence Hall of Science, the celebrations have only begun. The laboratory’s Winter Weeks, a science-packed holiday celebration for children and families, has returned this year, and its lineup is stacked. At its Public Science Center, visitors will have many activities to explore every day through News Year’s Day, from 10 a.m. to 5 p.m. (The center will close for Christmas and have a shortened day on Christmas Eve.) Come in the morning and start out with one of two short nature movies at the National Geographic 3D Theater, or head to the Ingenuity Lab to design and build structures to augment your Marble Run. In the afternoon, stay around to pet the laboratory’s resident pets at the Animal Discovery Room. In addition, there are special events around the holidays, like the limited screening of The Polar Express in 3D on December 23 and 24. The admission prices are $12 for adults, $10 children, and free for members, children age 2 or under, or Berkeley students and staff.