A Petri plate exposing stand is a device used in microbiology to hold Petri dishes while they are being exposed to ultraviolet (UV) light. The stand typically consists of a base with a UV light source and a frame or holder for the Petri dishes.

The purpose of the UV exposure is to sterilize the surfaces of the Petri dishes and the media inside them, in order to kill any bacteria or other microorganisms present and prevent contamination of the culture. UV light is effective at killing microorganisms by damaging their DNA and preventing them from reproducing.

When using a Petri plate exposing stand, it is important to follow proper safety procedures to avoid exposure to the UV light, which can be harmful to human skin and eyes. This may include wearing protective equipment such as gloves and goggles, and ensuring that the Petri dishes are properly shielded while the UV light is in use.