Hello, and welcome to Science Buddies! This is a great project, as it answers an important health question.
You are ABOSLUTELY using the scientific method during this experiment.
You have formulated a question (is iodine present in different salts?)
You are doing background research (why is iodine important?)
You are formulating a hypothesis (iodine is present in the salts you are testing)
You are conducting an experiment (you are testing different salts to see if iodine is present)
You will be analyzing the data and reporting your results.
Review the Scientific Method here:http://www.sciencebuddies.org/science-fair-projects/project_scientific_method.shtml
I hope this helps. Be sure to write back if you have any further questions. Good luck!