Ki (psi, chi, whatever you want to call it) balls are very difficult, if not almost impossible to make visible. It would take a large amount of energy. My friend and I tried this one game (I don't know what else to call it) where we made ki balls, and thought of and emotion (ie love, sadness, etc.) while we made them, and they got "programmed" with that emotion. We would then throw or give them to eachother and feel the emotion in them.