Talk to your children about how the mail works. Tell them that it is all just a big matching game. The sorters match the city/zip code to the proper location. Then the mailman sorts them and matches (delivers) them to the proper address. Bring in scales and let your children weigh mail (and boxes you provide) just like they do in the post office. They can then add correct postage (how much they feel it should have) For added fun have them deliver the packages to different areas of the classroom.
Everything Preschool >> Themes  >> Post Office >> Science