LYNN – Marshall Middle School teacher Florence DiPietro thought she was only going to help disconnect some wires when Principal Richard Cowdell asked her to the front of an assembly Tuesday.When her husband, Ross, and sons Chris and Ryan joined her in front of the students, she knew something was up.Shocked and slightly confused, DiPietro watched as Deputy Superintendent Cath-erine Latham and two Wal-Mart representatives appear next to her family to present her with a $1,000 check for the school in honor of being named the Boston Area Wal-Mart Teacher of the Year in 2008.”I had no clue about anything. I was shocked. When I saw Dr. Latham I just figured she was here to watch (Cowdell’s) presentation,” she said. “Oh my God, I had no clue that any of this was going on. No warning from my family or anything.”Someone on the board of the Wal-Mart Charitable Foundation nominated DiPietro, a sixth-grade science teacher at Marshall for 15 years, for the award without her knowledge. She was chosen as the one winner among 3,000 nominees from Lynn, Revere, Chelsea, Boston, Saugus, Nahant and Marblehead because of her dedication to students, unique teaching style and enthusiasm for learning.”She has a very caring attitude and she is good with children,” said Wal-Mart Charitable Foundation Representative Edmund Brown. “We are real thankful for the job she has done teaching these kids.”Cowdell spoke about DiPietro with pride as he described her energetic and outgoing teaching style.”She is a very, very energetic teacher. It is not uncommon to walk by her room and see her walking around with oak tag attached to her body with science vocabulary words written all over them,” said Cowdell. “She is the personification of someone who makes learning fun.”As sixth grade students serenaded their teacher with a standing ovation, DiPietro was left to wonder how her husband, sons and fellow faculty members were able to keep the surprise from her so well.”I cannot believe all of these people I know kept this from me,” she said. “I couldn’t do this without all of the other teachers here, now we are on a roll this year and we are going to have a great year.”Along with the $1,000 donation to the school, DiPietro will also receive a $100 gift card to Wal-Mart so she can purchase school supplies.”I see a lot of things come across my desk every day, some are good and others are bad, but this is very good,” said Latham. “I am thrilled for her and I am thrilled to be here.”