Dumb/Stupid Things You've Done...and Survived

We used to go to the Chemistry room after school to get extra credit, this was back in the mid 60s when we used to have real acids placed on open shelves in front of the students. The teacher was very cool but had no idea how devious we were. Either way, every time he left the room we would pitch a beaker or a graduated cylinder into the bushes just below the open windows. By the end of the school year we had a good sized lab at the home. But that wasn't the dumb part. One of the projects after school was to make a carbon arc. The teacher set up an iron (for ironing clothes), the old iron would draw quite a few amps which made it perfect for the carbon arc and the iron switch worked as a rheostat. Anyway, we would set up two carbon rods so they would stay a 1/2 apart, plug the iron into the wall and connect the iron wires to each rod in series. As you cranked up the power on the iron the arc would fire up. We had to wear dark goggles because the arc was super bright like a welding arc. The teacher made the mistake of leaving the room, as soon as he did we grabbed this super large (2 ft diameter) concave mirror that he had in the back of the room. We knew that concave mirrors concentrate light beams. We got the carbon arc fired up then me and my buddy held up this giant concave mirror and directed the carbon arc light out into the street. It was bright sunny day but you could still see the beam of light projecting from the classroom window. Being stupid as we were, we did our best to blind passing car drivers and damn near caused an accident. This is one of the least dangerous things we did back in the day!!