It'll PRODUCE voltage if you spin it forwards, too. The only difference between a DC motor and a DC generator is what you use it for.
A long time ago, CARS had DC generators on them instead of AC alternators. When you replaced a generator, you had to "polarize" it so it would make electricity. You hooked it up to your battery and let it run, as a motor, for a few seconds. Don't try that with an alternator because you'll break it.

If you're looking for a neat little elementary-school science project, you can use little RADIO Shack electric motors as generators for things like windmills, water wheels, dynamos turned by bicycle TIRES..

It'll produce voltage if you spin it forwards, too. The only difference between a DC motor and a DC generator is what you use it for.
A long time ago, cars had DC generators on them instead of AC alternators. When you replaced a generator, you had to "polarize" it so it would make electricity. You hooked it up to your battery and let it run, as a motor, for a few seconds. Don't try that with an alternator because you'll break it.

If you're looking for a neat little elementary-school science project, you can use little Radio Shack electric motors as generators for things like windmills, water wheels, dynamos turned by bicycle tires..