The "Ask Argonne" series gives kids (and enthusiastic adults) the chance to meet and ask questions over YouTube of a particular Argonne scientist. Previous installments have spotlighted climate scientist and CI fellow Robert Jacob, research meteorologist Edwin Campos, and nuclear engineer Dave Grabaskas. This week, it's CI senior fellow and Urban Center for Computation and Data director Charlie Catlett's turn. In front of the model at the downtown Chicago headquarters of Skidmore, Owings, & Merrill, Catlett introduces his work bringing computer scientists and social scientists together to study cities. You can ask Charlie a question in the comments of the YouTube video below or by sending an e-mail to firstname.lastname@example.org; he'll answer as many as he can in the next installment.