What got me involved with the Squishy Circuits program I posted about earlier was an electronics class I started for kids. I convinced my boss to let me do it as a library program (with library funding 😉 ), and  got my first experience in trying to teach to children. This was perhaps not the best idea I’ve ever had, but it’s been a lot of fun anyway.

Since the library is almost attached to the elementary school next door, we used a group of their kids to see how this program would go. The overall result: excellent. I started with a few experiments from the very excellent book Make: Electronics, but by the third group, I’d replaced some of the less interesting ones with my own experiments.

I started out by having the kids put the leads of a AA battery pack on their tongues, more because they found that exciting than for any real demonstrative reason. Then they shorted out their battery pack, and the wires heating up were a good example of resistive heating (though I didn’t go into much detail about that). An unintentionally exciting demo we did with the first group was putting a potentiometer in series with an LED. When they turned the pot down to 0, the LEDs were supposed to just burn out, but the cheap ones I got from China actually exploded, launching encapsulant pieces across the room (obviously I got less explosive LEDs for subsequent programs).

We also did a few short demonstrations of transistors, including one where the held a wire connected to the base, and one to the collector, and I explained that the tiny amount of current going through their body was enough to turn it on, just like pressing the button on the tact switch we used earlier. I also had them build the classic multivibrator blinky LED circuit, which they found pretty interesting. I showed them another version that had pots instead of fixed resistors, and used that to explain the function of the capacitors in the circuit.

Then I had them hook up a 555 buzzer circuit to a simple NPN amplifier circuit, and explained that the 555 was switching the transistor 400 times a second, which they thought was pretty impressive (I guessed 400Hz, as the pitch was somewhere close to A4, but who cares what the actual frequency was?). Just for fun, I also had them stick a pot into the 555 circuit to vary the pitch, which was fun for them, but annoying for me. For first group, I wired up the 555 circuit on their breadboards the day before, but for the last one, I actually put the circuit on a bit of veroboard that plugs into a mini breadboard quite nicely.

Since the kids I was working with were 11-12, I figured I could appeal to their interest in destruction. I brought out a small SLA battery, and shorted out the terminals with a bit of wire. After the smoke and flame, I compared it to the wires on the battery pack heating up from the first experiment, which they seemed to understand fairly well. Just for fun, I did something I experimented with as a kid. I attached some paper clips to the terminals and put a piece of mechanical pencil lead across them. With tens of amps going through a piece of graphite, it burned hot enough to light up the entire room. I took the opportunity to warn them that electricity can be dangerous, and the burning pencil lead could easily be them. I didn’t do the wire demonstration with all of the groups, because of the smoke, so with some others I had them tape some steel wool to a balloon and stick the leads from their battery pack into it. Of course, that caused the steel wool to melt, popping the balloon, which resulted in some screaming and plenty of laughter. The first time we did that, it drew a bunch of kids in from outside the room, which is just fine by me 😉

We like to give kids something at the end of our programs to keep them interested and wanting to come to the next one. The first group got the blinky LED circuit and 555 buzzer on little bits of veroboard. Let me tell you, it was an enormous pain in the ass to hand-wire ten of those stupid buzzers. So much in fact, that for the last group I actually had some PCBs fabbed for the buzzer circuit. Unfortunately, that ate enough of the budget that we couldn’t give them the blinky LED board, but they didn’t seem to mind. Though, I didn’t check my PCB design very well, and the holes for all the caps and resistors were far too small for the leads. I ended up sort of surface-mounting them onto the pads. I’m still not happy with it, but it worked well enough.

Once word got out about this program, all of the local elementary schools wanted us to come, and I went to two schools out of town. My boss wants to do this program again in the fall, but this time we’ll open it to the public. I like that idea, because with the school visits, they’re a captive audience. Not all of the kids were interested in electronics, although there were a few who really got into it. Hopefully, if we open it to the public, only people who are interested will sign up for it.

I really like sharing my hobby and my passion with these kids. Plenty of them weren’t at all interested, and that’s alright, people have different interests. There was about one or two kids in each group who really got into it, asked tons of questions, and started experimenting on their own while I was helping the other kids. It’s an amazing feeling to see that, and I sincerely hope I’ve inspired a future hobbyist or engineer. At some point during this, I realized that I’ve been tinkering with electronics since I was their age.

This has been an incredible experience for me. We’ve not done any programs this summer, because the Summer Reading program takes literally all of the library’s attention and manpower (over 2000 kids signed up this year!!!). I’m looking forward to doing more school visits and programs this fall, and I’m toying with the idea of an Arduino class for teens, we’ll have to see how that pans out.