Recently, I've been getting a slew of spams offering me free energy. Just plug this in, and it powers my home for free. Is that possible?
So I looked into the scam. Because free energy is, of course possible.
Most people will tell you that free energy isn't possible, but they're wrong. I know that, because I built a free energy device myself, when I was fourteen. It was a crystal radio.
A crystal radio needs no batteries. It works like this. You have an aerial, which is just a length of copper wire, and you have an earth, which is just a rod hammered into the ground. Between the aerial and the earth, you have a coil and a capacitor in parallel, and one of those is variable (I used a variable capacitor). Across those, you connect a rectifier (a diode, that's the crystal part) and a headphone, and by tuning the capacitor, I was able to listen to The Light Program (now called Radio 1, or maybe 2, I don't know).
This is collecting power from the radio waves and using it to power the headphone. No batteries are needed.
But it's not much power. A fraction of a watt. A very small fraction of a watt. Enough to power a sensitive headphone; not enough to power a house. How small? You'd be lucky to get 20 microwatts. So you'd need 50,0000 of them to get one watt of power, and one watt isn't much. A light bulb might be 40 watts. Two million crystal radios might power a light bulb.
So it's free energy, yes. But not enough to be useful.
So what's the scam? Well, they exaggerate. A lot. And you pay $49, or $99 for the plans, and you then have to spend money for the parts to build a small "generator", which shows you that they whole thing does actually work, although you don't get much power from it, and then you think about scaling it up by a factor of a million, and you don't do it. And if you demand your money back, and you paid by credit card, they will actually do a refund, because otherwise they'd get trouble with the credit card system. But very few people are going to ask for a refund. And so the scam goes on.
But I would urge any child to build a crystal radio; you make it out of things that you can find around you, and when it works, it's like magic, except it isn't magic, and it leads you into electronics, and computers, and fun stuff like that.