1) Front and center are the glass jars, which were my first vinegar battery. The two metals were copper wire and erector set pieces (maybe zinc plated steel or something?). The set of erector set pieces at the back were lowered into the solution to "start" the battery. While I could get some voltage from the 6 "cells", not much current could be drawn. For this reason, the vinegar battery was powering a low-current LED (housed in the black box), which lit and triggered the light sensor.
2) The funnel thing with a flashlight over it was a light-blocking transfer. Looks like a ball rolls into there and blocks the light from from the light sensor at the bottom of the tube. No idea why there's a battery sitting in there right now.
3) The final task this year was to ring a bell. You can see a black track at the very back of the box with some red boxes on it. The red things had bells and hammers on them, so as the ball rolled down the track, it hit the bells.
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