Proton with 300 GeV energy producing 26 charged particles in the 30 inch hydrogen bubble chamber at FERMILAB, c.1973.… https://www.rawpixel.com/image/3322287/free-photo-image-cc0-creative-commonsFree Image from public domain licenseThis hemispherical window was designed to cover the camera ports inside Argonne Lab's 12-foot (diameter) hydrogen bubble… https://www.rawpixel.com/image/3325630/free-photo-image-black-white-aec-argonne-labFree Image from public domain licenseA seated man in front of a chamber pot which is emitting bubbles, a group of people stand behind him; representing Gwyllym… https://www.rawpixel.com/image/13965316/image-cartoon-face-personFree Image from public domain licenseA Group of Men and Women Playing Chamber Music Within a Portico, Surmounted by Statues of Apollo and Female Figures, and… https://www.rawpixel.com/image/12491082/image-heart-face-personFree Image from public domain license