Mean square displacement of a macroscopic active particle with different self-propelled velocities. For a passive Brownian particle (v₀=0 cm s^-1), the motion is always normal diffusion [MSD $\propto t$], while for an active particle, the motion is diffusive ballistic at intermediate time scales [MSD $\propto t^2$], and again normal diffusion but with an enhanced diffusion coefficient at long time scales.