Petri dish (Petri plates), named after German Bacteriologist, are shallow dishes used for culturing cells, bacteria, and mosses. Nutrient Agar or other suitable growth media containing ingredients such as blood, cholesterol, salts, and carbohydrate etc. is widely used to culture bacteria for microbiological assays and experiments like those involving antibiotic and viruses (phages). Even Eukaryotes like yeast can be cultured on Petri plates. They have a lid which makes aeration possible. These are circular in shape and can be stacked one upon another. They are made of glass or plastic. Glass ones are autoclavable and reusable, while plastic plates are generally sterile and disposable. Petri plates are commercially available in wide range sizes with different diameters.