SKS Science Products offers a great selection of disposable plastic petri dishes that could be used in middle school biology labs for experiments involving cell culture, growing bacteria, mold growth and more. Our petri dish selection includes a wide range of sizes in clear, red, yellow or blue styrene plastic, as well as petri dishes with absorbant pads, contact dishes, and petri dishes marked with molded grid lines. A petri dish rack for easy and safe storage of petri dishes is also available.