Take the usual hangers, two identical container (it can be as large or medium-sized disposable cups and even aluminum cans of drinks, however, it is necessary to cut the cans at the top). The upper side of the tank, opposite to each other, make two holes, insert them
any rope and attach the hangers that hang, for example, on the back of a chair. Trim containers. Now, in such improvised scales pour or berries, or candy, or cookies, and then the children will not argue who got more goodies.