Make replica plates of a particular Petri dish
Contact is enough to transfer bacteria or other small organisms from the surface of one Petri dish filled with agar jelly to another fresh dish of agar jelly. This would allow you to copy the distribution of bacteria or other organisms from one plate to another so that they look very similar when the second plate has been left to grow for a while. This method could be repeated a large number of times, all within a short period of time, so that you create a large number of very similar Petri dishes.
- Obtain an existing Petri dish filled with solid agar jelly which already has colonies growing on it in multiple separate spots.
- Make or find a solid cylinder with the same circumference as the original plate or slightly smaller.
- Find or carve a wooden or plastic cylinder of the correct diameter.
- Cover the end of the solid cylinder with a piece of velvet or a comparable soft and uniform fabric.
- Wrap a piece of velvet or fabric around one end of the solid cylinder.
- Secure it in place by wrapping an elastic band around the circumference of the cylinder, on top of the fabric or by similarly tying it in place with string.
- Pull the fabric tight so that it forms a flat surface on the end of the cylinder.
- Press this covered end of the cylinder into the original plate without sliding or rotating one plate relative to the solid cylinder.
- Press this covered end of the cylinder into a freshly made plate filled with solid and sterile agar jelly without sliding or rotating one plate relative to the solid cylinder.
- Repeat steps 1 to 5 with fresh and unused materials for however many replicas you want to make.
- Wait for the replica plates to grow.