While in the bathroom , Bart notice that the water in the sink always drain counterclockwise . Lisa explain ( not entirely correctly ) that the water never drain the other way except in the southern hemisphere , due to the Coriolis effect , but Bart do not believe her . To confirm this , Bart make phone calls to various countries in the southern hemisphere . Lisa point out how expensive international calls are , so Bart decide to make a collect call instead . He call Australia , where a little boy answer the phone . Pretending to represent the " International Drainage Commission " , Bart is informed that the toilet and sink are both draining clockwise . Frustrated , Bart ask him to go and check the toilets of the neighbors . The call take six hours to complete , since the boy live in the outback , and Bart forget to hang up the phone . Later , the boy 's father is billed A $ 900 ( referred to as " dollarydoos " ) . The father call Bart and demand that he pay , but Bart only taunt him . Unfortunately for Bart , the father 's neighbour is a federal Member of Parliament , who report Bart 's offense to the Prime Minister — who is relaxing naked in a nearby pond .