lots of colonies on media with ampiciline - (Feb/15/2008 )

after transformation i grow the cells on two same plates
one has lots of colonies and the other has only one colony
i am working on the second one, but i was so confused with the one with lots of colonies???
i already put enough ampiciline in it but still so much, confused....

Could one plate be old and the other new? Ampicilin does degrade. So one plate has selection, while the other has no selection.

i prepared them at the same time so i think that may not be the cause....