societyforscience.org — Founded as Science Service in 1921, the Society for Science has been dedicated to expanding scientific literacy, access to STEM education and scientific research for more than 100 years.  (Click on Intel ISEF and Document Library) Required forms for experiments can be downloaded from this site.

apa.org/education-career/k12/science-fair — Science fairs, clubs, and student research (apa.org)

ipl.org/div/projectguide — Science Fair Project Resource Guide | ipl: Information You Can Trust

sciencebuddies.org — Science Fair Project Ideas, Answers, & Tools (sciencebuddies.org)

sciencefaircentral.com/students/scientific-projects/steps — Student Projects | Science Fair Central

spaceplace.nasa.gov/science-fair — Do a Science Fair Project! | NASA Space Place – NASA Science for Kids