“The spoon in the right hand is made of metal; the spoon in the left hand is made of plastic. Holding the two spoons at the same time helps you feel the difference between the weight necessary to play the melody (with a heavier touch) by the right hand as compared with the accompaniment played by the left hand (with a lighter touch).”
Also see the Hanon Variations found in the Shaak Technique Book for ways to approach this from a technical standpoint at the piano.