Show sample as: 72-frame QuickTime VR or 360-frame QuickTime movie loop.    My periodic table poster is now available! Silly putty. Silly putty contains about 4% boric acid, which is critically important for its bounce characteristic. See here for a reference. Source: Ed Pegg Jr Contributor: Ed Pegg Jr Acquired: 10 December, 2002 Text Updated: 11 August, 2007 Price: Donated Size: 1" Purity: 2%