Physics Experiments: How to build a simple generator

Simon came up with the idea to make this simple electric generator a while ago, but we had bad luck with the ceramic magnets we ordered: they had chipped ends and literally crumbled in my hands, which I found very dangerous. Simon was extremely upset when I told him we couldn’t use those magnets and had to order new ones, not ceramic but neodymium ones this time. Even though we had to wait for the new set of magnets, Simon had already prepared the square cardboard base with the long iron screw piercing it in the middle. He made it all by himself. Today we finally had the time and everything necessary for the project:

a 1,5 Volt, 40 mili-ampere miniature lamp;

coated copper wire,  0,25 mm thick;

and of course, two new 40 x 20 x 10 mm neodymium magnets (very strong, make sure to take precaution as such magnets can cause injuries when they jump towards each other — adult supervision required).

The generator works because of Faraday’s law, which states that a dynamic (moving) magnetic field creates electricity. The objective is to make sure the magnets can freely spin inside your cardboard box when you turn the iron screw. We put around 250 loops of copper wire around the box to create a coil (Simon actually counted). Carefully scrape the enamel off at the tips of the two loose ends of your copper wire and attach those to the lamp’s contacts.

Experimenting with electromagnetism

Here Simon tried to induce a magnetic field by allowing electric current to go through a conductor that is normally not magnetic (copper wire). The green stick is a magnet that got attracted to it once the circuit closed.

The copper wire also began to slightly attract the steel paperclips.

Back to circuits

Yesterday Simon asked me to buy new electronics software he found on the internet. It’s a realtime circuit simulator and editor called iCircuit. Simon has already built several circuits in it last night and there is so much more to discover. He was following Derek Banas’ tutorials on electronics.

Progress Documented

I wouldn’t publish this video if it wasn’t for one observation: this electricity project would have taken two hours just a few months ago. Now Simon assembles things like this within minutes, without using any manuals, just as a little break from anything else he was doing.

Cold soldering with Bare Conductive electric paint

On Sunday Simon found a Bare Conductive electric paint set in his shoe. Sinterklaas knows exactly what Simon wants! Today we tried cold soldering for the first time! The project involved building a paper house that would gradually light up as it gets darker in the room.

Besides the light sensor (or a Light Dependent Resistor), the circle also incorporated a transistor, a resistor and two LEDs.

It was quite difficult to keep all the components in place while the electric paint was still wet.

The waiting was enduring.

Tried blowing on the paint to make it dry:

Finally, the fun part: drawing the circuit:

The roof of the house on the inside:

Simon loved the effect of the gradual lighting up – when first placed in a dark room we saw almost no light but when we came back a couple hours later the house looked magical. Simon cuddled with it, took the roof off and reviewed the circuit again and again, and put the house next to his bed when falling asleep. I think we’d want to crawl inside of it if he could.

Is pencil conductive?

Simon was trying to make a circuit using graphite pencil as conductor but it wasn’t strong enough to make an LED burn. We actually measured the voltage with the multimeter and it was something like 0,3 V.

Kirchoff’s Current Law

On Monday Simon’s math tutor and I agreed that Simon should try some problem solving involving both math and electricity, considering his current interest. We chose Electricity and Magnetism > Current Behaviour > Kirchoff’s Current Law on Brilliant.org. I must say it wasn’t easy, but Simon said he understood it. We weren’t sure about that until Wednesday afternoon, when Simon discovered a new Adventures in Science video on YouTube on series and parallel circuits and screamed: “Mom, but that’s just Kirchoff’s Law!” and drew beautiful schematics.

The photographs above are showing Simon colouring the schematics his teacher drew. He had to colour them in certain ways to understand series and parallel circuits. These are the tasks he solved on Monday together with his teacher:

These are the circuits Simon was drawing for himself during the math lesson on Monday to help himself understand the topic better. It is an illustration of the Lily Pad Design kit, a wearable including conductive thread and sew-on LEDs:

And this is what Simon was drawing on Wednesday on his own, from memory (he said those also were the circuits of the Lily Pad Design kit, only he converted them in proper schematics now):

The new Adventures in Science video:

Ohm’s Law Applied to Lemons

Simon wrote a poster with electricity formulas (from memory) this morning and applied one of them (Ohm’s law) to his advanced lemon experiment.

We had already tried this experiment before but one lemon did not light an LED. Simon’s become more of an expert this time around. He used not one but 4 lemons now and measured the voltage (in Volts) and the current (in Amperes).

And he employed his sister as assistant.

The four lemons gave us almost 4 Volts!

Simon used his voltage and current measurements to determine the resistance:

He then decided that 24 Ohms was too little and added a resistor to his lemon circuit:

But with a resistor the LED light did not light up – apparently the voltage became too low. After all, the voltage is the resistance times the current. I suggested Simon try it again without the resistor, with the almost 4 Volts the lemons made. And it worked!

Joules per second

The new Adventures in Science video episode by SparkFun is out! This time on electric power.