Nedderman's method is used and developed to measure particle velocity inside a conical hopper by placing a mass of host particles, which dyed a different color, into an initially static bed. The velocities of glass beads and sand particles of different sizes were measured in a steel hopper and a Perspex hopper. The effect of wall friction on the solids flow was also investigated by increasing wall roughness with sandpaper stuck on the inside hopper wall.