Working with $scope.$emit and $scope.$on

How can I send my $scope object from one controller to another using .$emit and .$on methods?

function firstCtrl($scope) {
    $scope.$emit('someEvent', [1,2,3]);
}

function secondCtrl($scope) {
    $scope.$on('someEvent', function(mass) { console.log(mass); });
}

It doesn’t work the way I think it should. How do $emit and $on work?