Explore the fascinating quantum phenomenon of particle penetration through a step potential barrier in this 23-minute physics lecture. Delve into the counterintuitive behavior of quantum particles when their energy is less than the barrier's potential. Examine the Schrödinger equation, probability of penetration, and boundary conditions to understand how particles can "tunnel" through classically forbidden regions. Learn how the wave-like nature of particles leads to exponentially decreasing wave functions inside higher potential areas, challenging classical physics predictions.