JotaJ, it's not as silly a question as others seem to think. As you stated, you do need adapters to plug appliances from the United States into European sockets; that's because the European electrical system uses 50 Hz instead of 60 Hz and (more importantly) the voltage at the socket is 230 volts instead of 115 volts. It turns out, however, that the electrical systems of Canada and the United States (along with parts of Mexico) are all interconnected, which means they all must share the same electrical frequency (i.e. 60 Hz). The Canadians also use the same 115 volts at the socket.