Articulation for piano beginners. Non-legato:
Normally I start by introducing my beginners to a non-legato touch. I make them play the same sound on the piano (use a 3rd finger for the best support!) in a moving motion from one octave to the other, higher and higher on the keyboard. This, sort of say "diving" into the very "bottoms" of the keys with the relaxed hand (using full weight of your arm!) is free of any tension, and therefore, highly preferred over legato touch. While "diving"into the keys, a piano teacher needs to teach a student to listen/control to the sound he is making and make sure the touch/contact with the keys is soft, deep and flexible. The next step is to learn to play short simple melodies (shared between two hands, 3rd fingers only preferred) using non-legato articulation. Only after perfecting non-legato touch, a student can attempt to learn playing legato.
A few tips on staccato:
Staccato-(staccare) from Italian - means to separate. Piano teachers would agree - it is a bit hard to teach children to play staccato articulation on the piano. They do seem to grasp an idea of "spaces" between sounds and separation, but their staccato would come out quite flat and lack crispness. I believe the reason is simple. Students need to be taught to play/take the sound "out" of the piano, not "in". A short exercise of a quick "take off" from one key, flying and "landing" (diving) on the other key, may help. Teachers should make it simple-use the same fingers, go up and down the keyboard, right hand, left hand - as long as they get the touch right! Staccato touch can be compared to a trampoline, ping pong or a super rocket rapidly launching upwards. And of course, sometimes staccato demonstration from a teacher is always the best!