Electric motor

And yet it moves!

30 minutes


*Carefully review the general safety advice on the back of the box cover before starting the experiment. * Read the “Magnets and electricity” section of the safety guidelines carefully before proceeding. Do not let children under 8 years old handle small magnets. * Read the “Working with batteries” section of the safety guidelines carefully before proceeding. * Disassemble the setup after the experiment.


  • Dispose of used batteries in accordance with local regulations.
  • Dispose of solid waste together with household garbage.

Scientific description

What makes the disk with magnets  spin non-stop? As electricity flows  through the wire , a magnetic field  arises in the coil . The coil thus pulls the magnet  nearest to it.

In our motor, the magnetic field  of the coil  is alternately turned on and off using a reed switch —a special wire with a bulb. Two wires are sealed inside the bulb, and they only touch when located in a magnetic field . When the wires are connected, electricity begins to flow  through them, which turns the coil into an electromagnet.

The magnetic field  of the coil  repels the magnet near it, causing the disk  to rotate . The movement of the disk moves the other magnet away from the reed switch , disconnecting the wires and interrupting the flow of electricity. The magnetic field  around the coil  disappears. At this moment, the disk moves by inertia —without external influences.

Then, the magnet again approaches the reed switch, and the wires connect and once again begin to conduct electricity . Repulsion arises between the magnet  and the coil , which pushes the disk. And so, this sequence continues, and the motor keeps spinning.

That’s interesting!

A magnet affects the motion of electrons, but not just electrons! Other particles—such as protons and ions—also react to magnetic fields. They are called electrically charged particles. How do they react, and why does it matter?

Billions of charged particles (protons, electrons, ions) are flying from outer space towards Earth at high speeds. Take, for instance, solar wind—a stream of charged particles (primarily electrons and protons) originating from the Sun. This wind is dangerous for human beings. Fortunately, it cannot reach us at full strength because the Earth’s magnetic field changes the direction of movement of these charged particles. Some scientists presume that without a magnetic field, the solar wind would have easily “blown away” our planet’s atmosphere.