Given that your students—if they’re like mine—spend most of their time with their faces jammed in a small, medium, or large digital screen, they should at least know a little bit about how those suckers work, don’t you think?
I’m not going to get into how the programming or any of that jazz works, because who am I, Nick Burns? Instead, you can show those smelly little buggers how a simple electrical circuit works by building a rudimentary one alongside them. BE CAREFUL, as one could potentially get a little bit electrocuted. Safety first, second, and third!
That’s A Bright Idea!
For this Demo Science science demo, you’ll need a small light bulb (a flashlight bulb works splendidly), two batteries with voltage corresponding to that of the bulb, a few paperclips, a pair of alligator clip wires, and a bulb holder fit to hold your bulb. If you want to get super MacGyver-y about it, you can use foil and electrical tape instead of the wires—simply cut two 6” x 3” foil strips, fold or roll them tightly the long way, and use small strips of tape to hold them in place. Or, if you wanna be a baller, shot caller, twenty inch blades on the Impala, you can use 10-gauge wire and a handful of LEMO connectors and set up an unnecessarily-high-performance rig.
Install the bulb into the bulb holder (mind blowing stuff, I know), then connect one end of each wire, foil strip, or connector to each screw on the base of the light bulb holder. Take one of your loose wire ends and connect it to the negative end (“-”) of one of the batteries. Take the other loose wire end and hook it up to the positive end (“+”) of the battery. And, voila!
Wait a minute, nothing happened… But that’s by design, trust me. This is what we call “the scientific process”. It’s the process of science.
Disconnect the battery and get some more tape ready. Put the two batteries side by side, with one flipped so that there’s one positive and one negative terminal at each end. Wrap a strip of tape around the two to hold them together and create a half-butt battery pack.
Straighten out a paperclip and place it across one end of your battery pack so that it connects the metal “+” and “-” ends of the side-by-side batteries. Hold ol’ Clippy in place with more electrical tape, being careful not to tape over the metal battery ends. At the other end, tape one end of a straightened paperclip to each of the individual batteries—this will give you a total of three paperclips attached to your battery pack.
Reconnect the light bulb by clipping onto the open-ended paperclips (DO NOT attach a cable to the clip that connects the two battery terminals.) Bing bong, there it is!
In the first, intentionally-unsuccessful part of this experiment, you created an open circuit. Batteries provide electricity, of course, and lightbulb are powered by electricity, so why didn’t the bulb light up? in order to work, electricity from a battery has to flow out one end and back in (from the negative to the positive). Your battery-bulb-wire contraption allows the electricity to flow out, but doesn’t flow it back in. Hence, no lightshow.
In the second, successful part, you created a closed circuit, one in which the power from the battery can flow out and back in. By completing the circuit with the additional battery and paperclip connections, the negatively charged electrons that make electricity electricity can travel from the batteries through the clips to the wires to the bulb to the wires to the clips to the batteries, i.e., and complete loop or closed circuit.