Warm water freezes   more quickly than cold water. Sir Francis Bacon said that almost four hundred years ago. But few people believed him until 1970. In that year Canadian scientist Geoge Kell proved   the English physicist was right. Dr Kell filled one open bowl   with cold water. He filled another with warm water. He put both bowls to the same low temperature. The warm water froze   first. The lack   of covers on the bowls was the secret  . Some of the warm water changed into vapor.   It evaporated   into the air. This meant that less of the warm water was left to freeze. And so the warm water froze faster than the cold water. Sir Francis Bacon was   _  .
an American scientist a Canadian scientist a French scientist an English scientist