Subscribe (It's Free): http://bit.ly/10nP7dg Twitter: https://twitter.com/VsauceTwo *** CLICK "SHOW MORE" FOR LINKS AND SOURCES *** Hardtack (0:02) http://www.survivallife.com/2013/01/17/survival-food-101-hardtack/ http://www.youtube.com/watch?v=SGudU3VK