The Duke FEMMES group (Females Excelling More in Math, Engineering, and Science) held their annual capstone workshop on the Duke campus last Saturday, February 25th. This event featured a full day of STEM activities for more than 200 4th-6th grade girls from the Durham area. The Hsu-Kim group led a water filtration activity, where the girls experimented with filter designs using sand, gravel and activated carbon. They tested the efficacy of their filters for removing total suspended solids from test samples. We learned that some filter designs definitely worked better than others!