No scientist worth his title ever exposes himself needlessly to any potential hazards which confront him in his investigations. Thoughtful student scientists also will avoid any unnecessary exposure to ionizing radiation, particularly since bad habits acquired while doing student projects may be difficult to overcome later. Before undertaking experiments with radioactivity, consult your science teacher or project counselor. Any materials to be irradiated should be processed with professional equipment by persons trained and authorized to operate it. Use of radioisotopes, even in quantities exempt from license requirements, usually involves special laboratory facilities, techniques, and instruments, as well as the isotope itself. Make certain that all these will be available to you before you embark on your project. If possible, conduct all work with radioisotopes under the supervision of a trained, experienced isotope technician. At the very least, familiarize yourself with the specialized handling techniques required (see _Experiments with Radioactivity_ or _Laboratory Experiments with Radioisotopes for High School Science Demonstrations_, listed in Appendix III). Then follow them to the letter! APPENDIX V SUPPLIERS OF RADIOISOTOPES Your science teacher or project counselor may know of a nearby laboratory from which you can obtain the radioisotopes required for your investigation. If you wish to write direct to a commercial source, some of the suppliers of application-exempt quantities are: Atomic Corporation of America 14725 Arminta Street Panorama City, California Abbott Laboratories Box 1008 Oak Ridge, Tennessee Bio-Rad Laboratories 32nd & Griffin Avenue Richmond, California Nuclear Consultants Corporation 9842 Manchester Road St. Louis 19, Missouri U. S. Nuclear Corporation 801 N. Lake Street Box 2022 Burbank, California Nuclear-Chicago Corporation 333 East Howard Avenue at Nuclear Drive Des Plaines, Illinois New England Nuclear Corporation 575 Albany Street Boston, Massachusetts Union Carbide Nuclear Company Oak Ridge National Laboratory Isotope Sales Department P. O. Box X Oak Ridge, Tennessee ChemTrac Corporation 130 Alewife Brook Pkwy. Cambridge 40, Massachusetts Nuclear Consultants, Inc. 33-61 Crescent Street Long Island City 6, New York APPENDIX VI INTERNATIONAL SCIENCE FAIR RULES _Finalists who enter the ISF must follow these rules without exception._ The following code refers to the ISF rules listed below: S—School Fairs (recommended) R—Regional Fairs (recommended) I—ISF (required) S-R-I Categories established for grouping and judging science projects at the ISF are: