5. (5 pts) Briefly explain, from a thermal perspective why there is an "optimal" spacing between the inner and outer glass panes in double-paned windows. 6. (5 pts) Consider a double pane window being designed for an extreme climate, for which there would be a greater temperature difference between the inner and outer glass panes than in typical designs. Should the spacing between the panes be increased, decreased, or unchanged in this case? Provide a physical justification for your response.