Eisco-Demonstration-DC-Motor-Eisco-PH1242-P-This-demonstration-DC-motor-has-been-specially-designed-to-help-students-learn-about-electromagnetic-forces-in-motors-P-P-All-parts-are-clearly-visible-&-the-polarity-of-the-magnets-can-be-reversed-to-change-the-direction-of-rotation-It-can-be-used-with-a-rheostat-not-included-connected-in-series-to-observe-the-change-of-speed-caused-by-a-change-of-current-P-P-The-commutator-&-sliding-contacts-brushes-show-how-the-polarity-of-the-vo