The invention discloses a mechanical speed fluctuation demonstration instrument, comprising a drive mechanism, a balance damping mechanism, a speed fluctuation detection device and a
laser display and writing mechanism, wherein the drive mechanism comprises a
drive motor and a
flywheel; the balance damping mechanism comprises a resistance-trimming bolt, a support frame subassembly, an elastic
damper, a slide block, a guide rod, a
crank circle, a
crank and a baffle block; the speed fluctuation detection device comprises a traction bar, a guide shaft, a box body, a transport cover, a shaft, a
rubber sheet, a lock bolt, a sealing bearing, an O-shaped ring, a T-shaped joint, a protecting shell and an elastic film; the
laser display and writing mechanism comprises a rack, a driving shaft, a driven shaft, a secondary motor, a
paper tape, a
laser pen bracket, a laser pen and a color pen; and the driving shaft, the driven shaft, the secondary motor, the
paper tape, the laser pen bracket, the laser pen and the color pen are fixed on the rack. According to the device, a teacher can effectively display the speed fluctuation and adjust the learning content; a '
black box' in the traditional training aid demonstration process is avoided; the condition that students understand the speed fluctuation and adjust the learning content is facilitated; and understanding faults are avoided.