Ice Spikes Explained

Why do spikes form on ice cubes? Without them the world would be vastly different. Awesome Jingle by Accent: http://bit.ly/AccentVe Thanks to Prof. Stephen Morris from UofT: http://bit.ly/1GFANBE Filmed in part by Martin Marek in Olomouc, Czech Republic Time lapse of a growing ice spike by Lesley Hill, Russ Sampson and Edward Lozowski, with technical help by Kenny Lozowski. Ice spike image by Dan and Lynn Wolaver: http://wolaver.org/log/09.11.29.htm Concerned ice spike video by rocknut420: https://www.youtube.com/watch?v=GwM0we_t94c Earth footage courtesy of NASA: https://www.youtube.com/watch?v=G4BPOEmugtM Ice vase image by PgunnG: http://www.reddit.com/r/pics/comments/1voeqk/so_i_walked_outside_this_morning_and_found_this/ Second ice vase image by A K Haart: http://akhaart.blogspot.com/2015_01_01_archive.html