Organize your microorganism into 10 petri dishes.
Insert your units of antibiotic into the 10 petri dishes, using an increasing amount of antibiotic with each subsequent dish. For example, place 1 unit of antibiotic in the first dish, 2 units in the second dish, and so forth.
Make note of the petri dish in which the growth of the microorganism is inhibited. The number of units you have placed in that petri dish is the MIC of your antibiotic. For example, if the petri dish you placed 4 units of antibiotic into is the first dish to show inhibited growth, the MIC of the antibiotic is 4 units.