A bottle rocket launches at the Water Rocket Festival in Pocatello. | Courtesy ISU POCATELLO – Learn physics and have some fun at the same time at a community event this weekend. On Saturday and Sunday, Idaho State University’s Department of Physics will hold its annual Water Rocket Festival at Tydeman Park — North 8th Avenue and East Young Street. The first 100 kids who arrive get to build and launch their own bottle rockets. “The hope is to sn…