Every now and then someone reports a physically visible psi ball, but it's pretty uncommon and most people don't believe them. They are extremely psychically visible though! I've often created psi balls that even non-magical friends were able to focus on and mentally "see" the color of.
remember that if you are aiming to create a specific effect learn to generate, focus and direct more than just psi energy, psi is mental energy which has it's uses, but energies such as Chi and Ki have the ability to cause more of a direct physical effect due to their vibrational rates, remember that all different energies have different densities, vibrational speeds and thus different uses accordingly, take the time to understand and fully experience any energy you encounter which comes from your own vessel.
Chi is a internal energy, also known as prana, it is our own personal internal flow. Thus as you live, breath, go through your entire respiratory process your cells create energy, that energy moves along your energy pathways throughout your entire body.
Ki is a external energy, it is the universe as a whole's personal flow, it is a byproduct of motion and kinetic forces on a cosmic level, thus the friction created by light as it moves through the vacuum of space as it loses speed creates Ki, the momentum and inertia from a star dying or dropping into a blackhole creates Ki. Ki can only be channeled through the vessel, not generated by it.