Ironically, just as it became feasible for the first time to make superconductors in a High School science lab, many of the necessary supplies and equipment began to become more and more difficult to obtain.

The Coors CD-20 alumina dishes (Coors Ceramics part number 65592) are rapidly being discontinued by distributors, but they are still available.  A substitute is the AL-23 combustion tray sold by Alfa Aesar.  Alfa stock #33184 is a 50 mm. diameter dish very similar to the Coors CD-20, although the Coors dish generally costs less.  The Alfa Aesar dish sells for $78.90.  Alfa Aesar may have a smaller dish at a lower cost than the 33184.

Alfa Aesar also can supply (to legitimate laboratories) the chemicals necessary for making ceramic superconductors.

The address for Alfa Aesar is:

Alfa Aesar
30 Bond Street
Ward Hill, MA 01835-8099

Phone: (800) 343-0660

To find a local source for liquid nitrogen, look in your local yellow pages under "Gas - Industrial, Medical, Etc. - Cylinder and Bulk." Most companies will sell science teachers a small amount if they have a suitable container.  Liquid nitrogen costs less than one dollar per liter, but there is usually a minimum charge of $10 to $20.  Alternatively, many hospitals or dermatologists will supply a small amount of liquid nitrogen to a science teacher.

If you do not have a suitable container for liquid nitrogen, they can be purchased from most distributors of science education or laboratory equipment.

A less expensive option is to obtain a good-quality stainless-steel thermos, and drill a 6 mm. vent hole in the plastic cap.  The vent hole is an absolute requirement for venting the liquid nitrogen as it boils off.  Such a modified two-liter or two-quart stainless-steel thermos will safely hold liquid nitrogen for 24-48 hours before it all boils away.  A one-quart thermos will also work, but the liquid nitrogen will only last a few hours before boiling away.