Summary:

Condensation on the inside lid of Petri dishes is a universal problem in the laboratory. Condensation problems result when the temperature of the inside lid of a container falls below the temperature inside the container itself. Condensation can take the form of either a light fog or large water droplets. When large water droplets form, they can drop from the lid onto the contents of the container, displacing the contents and creating water-soaked microenvironments. When a light condensation is formed, the contents of the container are often obscured, which makes critical observations difficult and photo documentation of the contents of the dish can be very frustrating.

Researchers at The Ohio State University have eliminated condensation in Petri dishes by a simple modification in Petri dish design. By increasing the thickness of the polystyrene in the top portion of a standard Petri dish lid, the lid was buffered from small temperature changes and condensation was reduced or eliminated. The side walls of the Petri dish remain the same thickness so condensation will preferentially form on the side walls, and water droplets run down the side wall to be reabsorbed by the medium in the dish.

The invention does not require large changes in manufacturing basics. Containers will still be manufactured from polystyrene, which is optically clear, inexpensive and a good insulator (low thermal conductivity). The new Petri dish lid will be thicker on the top surface and sides of the lid should remain the same thickness.

Potential Applications:

All laboratories and other research and development facilities

Advantages:

• Condensation is virtually eliminated
• Does not require major manufacturing changes
• Made with inexpensive materials