On a visit to a school in Edinburgh today, an S3 Intermediate 2 class were making electric motors. One group got their kit working in about 25 minutes (including cutting and stripping wire, winding the armature and fitting the bushes), so entertained themselves by fixing red and blue card on either side of the armature faces, predicting a cool purple colour would be seen when the motor ran.
Here it is, in all its purple glory. Click the image for a full sized version.
As one commentator put it, “a proper experiment! there is hope for our children after all…”