Component guide
How to Use the Motor
- Grades 3-8
- 10 minute activity
- NGSS 4-PS3-4
Quick answer
A motor turns electricity into motion. To use one in a play dough circuit, push one motor wire into each of two pieces of conductive dough connected to the battery holder. A motor has no polarity, so it works either way around: swap the wires and it spins the other direction.
Try it with dough
Make the motor spin
You need
- Battery holder with 4 AA batteries
- Conductive (salty) play dough
- 1 motor with fan blade
Steps
- Make two short, thick pieces of conductive dough and set them a finger-width apart.
- Push the red battery wire into one piece and the black wire into the other.
- Push one motor wire into each piece of dough, close to the battery wires.
- Switch the battery holder on and watch the fan spin.
- Switch off, swap the two motor wires and switch on again.
What happens
The fan spins. When you swap the motor wires, it spins the other way.
Not working?
- Motors need more electricity than LEDs. Use short, thick pieces of dough and keep the motor wires close to the battery wires.
- Push all the wires deep into the dough.
- Give the fan a gentle flick to get it started.
- Try fresh batteries.
How does a motor work?
Inside the motor is a coil of wire. When electricity flows through the coil, it becomes an electromagnet. Around the coil are two permanent magnets, one with its north pole facing in and one with its south pole facing in.
The electromagnet is pushed by one magnet and pulled by the other, so it turns. Every half turn, a part called the commutator flips the direction of the electricity in the coil, so the pushing and pulling keeps going and the motor keeps spinning.
Why swapping the wires reverses the motor
Swapping the wires sends electricity through the coil in the opposite direction. That flips the electromagnet's north and south poles, so every push becomes a pull and every pull becomes a push, and the motor spins the other way.
That is also why a motor has no polarity. It runs either way around, it just changes direction.
Motors can make electricity too
A motor turns electricity into motion, but it also works in reverse. Spin a motor's shaft and the magnets moving past the coil push electricity through the wires. Used this way, a motor becomes a generator.
Wind turbines, hydroelectric dams and most power plants make electricity with giant generators that work on the same idea.
Key words
- Motor
- A part that turns electricity into motion.
- Electromagnet
- A coil of wire that becomes a magnet when electricity flows through it.
- Permanent magnet
- A magnet that is always magnetic, like a fridge magnet.
- Commutator
- The part of a motor that flips the direction of electricity in the coil so it keeps spinning.
- Generator
- A machine that turns motion into electricity.
- Energy transfer
- Changing energy from one form to another, like electrical energy into motion.
For teachers
Motors are a great fit for NGSS 4-PS3-4: apply scientific ideas to design, test and refine a device that converts energy from one form to another. Challenge students to build a dough creation with a moving part, then explain how electrical energy becomes motion. Find free lesson plans on our education page.
Watch: how to use the motor
Motor questions
Does a motor have polarity?
No. A motor works either way around. Swapping the wires makes it spin in the opposite direction.
Why isn't my motor spinning?
Motors need more electricity than LEDs. Use short, thick pieces of dough, keep the motor wires close to the battery wires, push all the wires in deeply, use fresh batteries and give the fan a gentle flick to start it.
How do I make the motor spin the other way?
Swap the two motor wires. Reversing the electricity flips the electromagnet inside the motor, so it spins in the opposite direction.
What is the difference between a motor and a generator?
A motor turns electricity into motion. A generator turns motion into electricity. They are built from the same parts, magnets and coils of wire, and a small motor can work as a generator if you spin it.
Can I use a motor and LEDs in the same circuit?
Yes. Put them across the same gap or different gaps. The motor draws more power than the LEDs, so the LEDs may glow a little dimmer while it runs.
Where are motors used?
Everywhere things move: fans, toys, drills, washing machines, car windows, electric cars and the vibration in your phone.
Printable guide: Components Explained (PDF)
Next, try a project
Build the Submarine Project A free step-by-step project with a spinning propeller.