Petri Dish, Plastic

Quick Answer: A plastic Petri dish is a shallow, flat, round dish with an overlapping lid, moulded from clear plastic and used for growing cultures, germinating seeds and holding specimens for observation. It is lighter and less breakable than a glass dish, which makes it the usual choice for school and college practicals.

Plastic or Glass? What the Material Changes

The name comes from Julius Richard Petri, the German bacteriologist who described the design in 1887 while working in Robert Koch’s laboratory. The shape has hardly changed since, but the material has: most dishes in use today are plastic, and the plastic chosen decides what the dish can do.

Polystyrene gives the clearest view and is the usual resin, but it cannot be autoclaved and many solvents attack it. Polypropylene dishes are cloudier yet tolerate autoclaving, so they can be reused a limited number of times. Glass remains the option for repeated heat sterilisation and for solvent work. If autoclaving matters, check the resin of this listing when ordering.

Because the base is flat and thin, a plastic Petri dish also works as a small viewing tray under a hand lens or stereo microscope. Teachers use it to hold pond water with its organisms, soil animals, leaves, insects or crystals, and to run short experiments on diffusion through agar or on how seeds respond to light and water.

Specifications

Applications

• Observing pond organisms or soil invertebrates under a stereo microscope
• Diffusion demonstrations with coloured solutions or indicators set in agar
• Germinating seeds to test the effect of light, water or temperature
• Growing crystals from saturated salt or sugar solutions
• Simple culture work, provided the dish is sterile and of a suitable plastic

Care & Use

• Wash dishes used for non-culture work in warm soapy water with a soft cloth; scouring pads scratch the base.
• Keep each lid with its own base so it sits evenly.
• Never put a plastic dish on a hot plate or near a flame.
• Store dishes stacked in a closed box or sleeve to keep dust off the viewing surface.

Why Choose LabEquip

As a laboratory Petri dish supplier to schools and colleges, LabEquip is most often asked for plastic dishes for general practical work rather than culture alone. The dish sits in the Biology Lab Products range; the culture Petri dish page covers agar plating in more depth, and the contact page is the place to specify quantity and resin.

Frequently Asked Questions

Who invented the Petri dish?

It is named after Julius Richard Petri, a German bacteriologist who described it in 1887 while working with Robert Koch. It replaced the earlier practice of growing bacteria on flat glass plates kept under bell jars.

Is a plastic Petri dish safe for school use?

Plastic dishes are safer than glass for young students because they do not shatter into sharp pieces. For culture work in schools, plates should be sealed after inoculation and not reopened once organisms have grown.

Can I heat a plastic Petri dish?

Not directly. Polystyrene softens at roughly 90 to 100 degrees Celsius and polypropylene at somewhat higher temperatures, and neither belongs on a flame or hot plate. Use a glass dish for anything that must be heated.

Which plastic are Petri dishes made from?

Most are polystyrene, chosen for clarity. Polypropylene is used for dishes that must be autoclaved, although it is less transparent. Specialist dishes for cell culture carry surface treatments.

How can I stop condensation clouding the lid?

Let hot agar cool before pouring, leave poured plates at room temperature for a while before refrigerating, and store or incubate them lid-down. Vented lids also reduce condensation.

Can a Petri dish be used for chemistry experiments?

Yes, for small-scale work such as precipitation spots, indicator colour changes, evaporation and crystal growth with aqueous solutions. Keep organic solvents out of plastic dishes, which they can dissolve.

Last Updated: September 2026