Iowans are invited to celebrate “hat day” next Friday as a new exhibit featuring dozens of hats opens at the State Historical Museum. Visitors to the state historical building are invited to wear their favorite headgear next Friday, be it a fedora or a fireman’s helmet. Michael Smith is the curator of the “Hold on to your hat” exhibit which opens to the public on the 21st.Smith says the wearing of a hat can send all sorts of signals such as rites of passage like the wedding veil.Smith says the exhibit has hats which are a form of personal expression, and others which offered protection such as football helmets.Governor Tom Vilsack has declared next Friday “Iowa Hat Day” as “Iowans tip their hats to good ideas.” As you may know, Vilsack’s wife, Christie, is quite partial to hats and the hat Mrs. Vilsack wore to her husband’s inauguration is part of the display.