Vortexers, or vortex mixers, gently agitate liquid samples by creating a vortex motion within the sample tube. Vortexers are composed of a drive shaft, oriented vertically, and connected to an electric motor, encased in a plastic or steel housing. The top end of the drive shaft protrudes from the housing and attaches to a micro-tube cup adapter or rack designed to accommodate microplates or multiple test tubes. Simple vortexers turn on automatically when a micro-tube, containing the sample, is pressed into the rubber cup. Advanced vortexers include analog or digital controllers with on/off switches, mixing speed controls, vortex timers, and alarms.