Abstract: The flea in the magnetic stirrer can steadily rise and suspend in the viscous fluid

with the change of the speed of magnetic stirrer. The motion of the flea in magnetic levitation

is analyzed theoretically by means of dy-

namical equation， and the parameters affecting the stable levitation are investigated

experimentally by means of var- iable controlling. The experimental and theoretical results

show that the higher the fluid viscosity coefficient， the lower the suspension height of

the flea. As the driving speed of magnetic stirrer increasing， the flea oscillation angu- lar

velocity ωw strengthened， rotation angular velocity ωs weakens， suspension height decreases;

Smaller flea tended to be more stable in the center， and smaller beakers tended to provide an

initial stable state. When the initial height zb from the bottom of the flea is fixed， the

higher the driving speed， or when the driving speed is fixed， the higher the initial height zb

from the bottom of the flea， the smaller the corresponding swing amplitude.

Key words: magnetic stirrer, viscous fluid, dynamic stability, IYPT