Science Fast Break By Commonplace Fun Facts on January 19, 2016 • ( Leave a comment ) When glass breaks, the cracks move at speeds of up to 3,000 mph (4,828 kph). source Share this:LinkedInEmailFacebookRedditTwitterPrintTumblrPocketPinterestTelegramWhatsAppSkypeLike this:Like Loading... Related Categories: Science Tagged as: breaking glass, cracks, glass, Speed