My German colleagues were laughing at the way I pronounce google, and it led to a discussion.
With words like google, yahoo, poodle and loose, the oo has a sound similar to the German ü sound.
With words like good and book, it is more similar to how Germans pronounce a oo sound.
For words like door we are not sure if that is the same or different.
The Germans want to know what the pronunciation rules are so they can improve their English. I am guessing that there are no rules, and the pronunciation possibly comes from the original language that the word comes from.
Are there any rules? Is there any reason why there are two different pronunciations? Can non-native speakers work out the correct pronunciation by looking at the other letters in the word or the etymology?