A magnetic propeller

Starting a propeller using a battery

Safe­ty pre­cau­tions:

Warn­ing! Only un­der adult su­per­vi­sion.


  • АА bat­tery;
  • screw;
  • cop­per wire;
  • two round neodymi­um mag­nets;
  • pa­per pro­pel­ler.

Step-by-step in­struc­tions

Care­ful­ly place a pa­per pro­pel­ler be­tween two neodymi­um mag­nets. Then place the head of a screw on one of the mag­nets, and touch the sharp end of the screw to the neg­a­tive (flat) pole of an AA bat­tery. Use a fin­ger to press one end of a cop­per wire to the pos­i­tive pole of the bat­tery, and touch the oth­er end of the wire to one of the mag­nets. The pro­pel­ler spins!

Im­por­tant! Do not let the pro­pel­ler spin too fast. Wear safe­ty glass­es.

Process de­scrip­tion

When the cir­cuit is closed, an elec­tric cur­rent be­gins to flow, cre­at­ing a mag­net­ic field that acts on the neodymi­um mag­nets. At the same time, the mag­net­ic field acts on the elec­tric cur­rent. In the re­sult­ing sys­tem, elec­tro­mag­net­ic en­er­gy tends to con­vert to me­chan­i­cal en­er­gy. As a re­sult, the mag­net be­gins to ro­tate, sus­pend­ed on the mag­ne­tized screw. The move­ment of the sys­tem is hin­dered only by fric­tion at the tip of the screw, which is neg­li­gi­ble due to the small area of con­tact to the neg­a­tive pole of the bat­tery.

Many amaz­ing and safe ex­per­i­ments are wait­ing for you in the MEL Sci­ence sub­scrip­tion!