I guessed they would have different origins, but a quick search proved me wrong. They are both from Old English. The difference comes down to the mess caused by The Great Vowel Shift and the delightfully named:-
Foot-goose merger
The foot-goose merger is a phenomenon that occurs in Scottish English, Ulster varieties of Hiberno-English, Malaysian English and Singaporean English, [1] where the vowels /ʊ/ and /uː/ are merged. As a result, pairs like look/Luke are homophones and good/food and foot/boot rhyme. The merged vowel is usually /ʉ/ or /y/ in Scottish English and /u/ in Singaporean English.[2] The use of the same vowel in "foot" and "goose" in these dialects is not due to phonemic merger, but the appliance of a different languages vowel system to the English lexical incidence [3]. The full-fool merger is a conditioned merger of the same two vowels before /l/, making pairs like pull/pool and full/fool homophones.
Having just finished a large plate of delicious rabbit curry, the full-fool merger has a certain attractive ring to it as well.
The International Phonetic Alphabet is an exotic creature, and one I want to keep at a safe distance. But if you want to hear examples of some of the symbols used in the passage above this web site is quite fun:
http://web.uvic.ca/ling/resources/ipa/charts/IPAlab/IPAlab.htm