This past weekend, we finished up Giovanni and Antonio’s science fair projects. We wound up doing two projects dealing with electricity. We had changed plans a few weeks ago as our original idea was to grow plants. I don’t know what the kids were thinking when they picked those projects. Electricity is so much cooler than growing plants in different soils and seeing how they grew. I mean, if we were growing carnivorous plants, that might be pretty cool. But I digress.
Antonio’s project was called “Is this connected to that” and it was about an electrical circuit and conductive materials. Antonio build a tester himself from instructions on the intertubes. We got a little buzzer, some alligator clips, some wire, a battery holder and a few batteries. Here is a diagram of what he made:
Antonio generated a chart of materials that conducted electricity. We also tried a few light bulbs and saw if we could make them glow. We couldn’t make the household ones glow cause those require a lot more voltage. We had a few small 3V tiny light bulbs that lit up fine. When it came time for an Ikea 12V bulb, we had to use 8 batteries in series. Here is a picture of that bulb all glowy:
That’s our unit with 8 batteries, here is the finished 3V tester with buzzer:
We also experimented with a lamp, seeing that the switch broke the circuit and removing the light bulb also broke the circuit. The cool thing was that all of this was new to Antonio so he learned a ton. I also learned that 8 batteries put together in series can create quite the sparkle show if you don’t pay attention.
Giovanni’s project saw the construction of the world’s simplest motor. Here are the components:
This was a pretty fun project. We used neodymium magnets, which are always a lot of fun. They are also a pain in the ass cause they draw things from quite a distance and it’s not uncommon to get pinched in a sudden and painful manner. The laser tachometer was very cool. It’s rated at measuring speeds up to 100k rpm. We were able to get this motor spinning at 4900 rpm, which is pretty damn fast. We spent a lot of time eliminating friction and making sure the motor was balanced. WD-40 was our friend. Giovanni and I had a little contest to see who could get the thing spinning the fastest. We did a bunch of trials with different number of batteries.
Here was some of our raw data:
|Magnets||Top Observed Speed in rounds per minute (rpm)||Notes|
|2||200||Could not really get it going|
|4||1900||Well balanced, low friction|
|4||1200||Well balanced, low friction|
|5||1200||Well balanced, low friction|
|5||1520||Well balanced, low friction|
We massaged the data and were able to see these trends:
We would have ran a lot more trials to get a better statistical distribution, but getting the thing up to speed was not easy. Sometimes we could not get friction eliminated. Sometimes we expecte the batteries were getting drained. It really wasn’t easy. If I were more handy, I would have tried to build some kind of rigging that would keep things more stable, but I’m not that handy.
Until next year!