This is an activity that I have used when doing a pirate theme in my classroom. I have students complete it in the first week, seal their letters in small bottles (miniature coke bottles, water bottles, etc.) and turn their bottle in to me. I redistribute the letters at the end of the year for students to read and reflect on how they have grown.
The procedures are included, as well as printable pages for the students. Each printable page is presented in both color and black and white.