As students of all ages adjust to online classes during the pandemic, one course that can be hard to teach virtually is science. But for some teachers, where there's a will, there's a way. WBEZ's Kate McGee reports. Also, some increasingly popular air conditioning systems don't bring in enough fresh air. University of Maryland environmental health professor Donald Milton joins host Robin Young to discuss one type of ultraviolent light system that disinfects inside air called upper-room UV.