We walk past things that would have made Newton fall on his backside in wonder and fear, yet we do this without even raising an eyebrow. Marvels of engineering, of technology, of science, get at most a sideways look of annoyance, because apathy has replaced curiosity for the modern human and whatever manages to distract us for more than a second apparently deserves getting upset over. I mean, what we were thinking or doing was way more important than that, right?
Technology these days is either so advanced it’s mind boggling to try to understand it therefore we just accept it and move on, or we’re so cocooned in it from day -9 months we just assume it’s natural. Either way, understanding technology seems to be a step we can skip in favor of using it. Anybody else than me has a problem with that? I think… No, I know I haven’t been making sense for the past month or so, my texts going darker by the minute, hell, you’d think I’d be wearing a tin foil cap by now, hiding somewhere in my basement muttering “aliens, they’ve come for me..”. Aliens don’t bother with me, they’ve got their self esteem to worry about. Yet, I keep wondering whether I’m the only one who sees the world like this.
Ask any adult if you can have a radio transmitter or receiver work without a battery. If they say yes, then ask how. Most will say it can’t work like that, and those who think it can, have no idea how that would work – they said yes only because today’s technology seems so outrageous and crazy it’s a safe bet to think we could do just about anything we want, given enough time and brain power. We assume anything is possible and by a stretch of imagination we can do absolutely anything – if we can’t do it now, the technology just hasn’t been invented yet but it will be, someday. That’s magical thinking. Technology can’t make everything possible – the laws of physics don’t work that way. We can jury-rig, we can tinker, we can go around, we can even fake it – but we can’t break reality. It’s no big secret I’m a big fan of magic shows, not because of what they do or how they do it, but because of that adrenalin rush one gets when the music gets heavier and you just know you’re about to be flimflammed. Magic means tricking the senses, not breaking the laws of physics, and that’s exactly what raises the hair on my… neck.
A century ago, big things happened. In November 1915, Einstein’s thought experiment was presented to the Prussian Academy of Science – his now famous field equations on general theory of relativity. He’d have flipped his marbles if he ever saw his contributions to technology used so freely by people that can’t even understand it. It’s like magic and we just happen to witness it and yet, there’s no sense of wonder tied to it. Back to our question, how to make a radio work without a battery? Well, first of all, don’t rush to answer. Yes, it can use solar power. No, that’s not the correct answer, that’s the lazy answer, the trivial solution – and I’ll bet most of you have no idea how solar power works. The mark of the scientist – and by that I mean the actual definition of that word, the user of the scientific method, the person engaged in the systematic pursuit of knowledge, even if it’s a layperson – is not only finding the right answers, it’s also asking the right questions. Here, we ought to begin by asking a question: “Define radio. What should it do?”.
If by radio we mean a device to produce sounds we can hear, a receiver, there’s more than one way to do it. Because it requires speakers, it can be big and if it can be big, we can strap some solar cells on it – so one way to do it is by way of solar power. How does that work, though? Now you rush to answer… Well, Einstein got the Nobel Prize for this – it’s called the photoelectric effect. Well, no. Not exactly. It’s not Einstein’s, it’s Becquerel’s and it’s not the photoelectric effect it’s the photovoltaic effect. Solar power means photons hit something, electrons get energy by being hit by photons and start moving around inside that something – this is the photovoltaic effect. The photoelectric effect is a bit different, because of what happens to the electrons that got hit – they will move, but instead of never leaving the source material like in the photovoltaic effect, they actually escape it. The short and easy answer is in the energy of light – shine photons on a material and electrons move around – you can make them move in one specific direction and you have electricity (photovoltaic effect), shine photons with higher energy on a material and electrons are bounced off that material entirely (photoelectric effect). So by harnessing light we can power circuitry thanks to the photovoltaic effect. Easy peasy. It’s one way to do it. Is there another? Yes, yes, there is. Forget about electrons, think low-tech.
You can use a mirror to focus sunlight into a closed container filled with something (water, ether, whatever works), to make it boil, expand or maybe turn into steam – and use that to power a wheel, rotating a coil of wire inside a magnetic field – this is an application of Faraday’s law of induction and Maxwell’s equations which state that a changing (time variable) magnetic field creates an electromotive force across a conductor exposed to it. Moving the coil of wire across the magnetic field is exactly the same as a variable magnetic field moving on a fixed coil of wire, you just look at it in a different way. Think of what powers your bicycle headlamp – a magneto.
Now we got 2 ways of powering that radio device. Do we go on? Sure, beats being bored to tears. Let’s talk other sources of power, since at night we could find light lacking. What else is there? What other types of radiation are there? Acoustic radiation, apparently. Jacques and Pierre Curie discovered piezoelectricity, which is a tongue-twisting way of saying that certain materials create an electric charge when a mechanical force acts on them. The very nice real-world application of this? Sonar. Structural safety measurements. Sound/ultrasound induces vibrations in something that in turn generates an electric charge. Any more bright ideas? Well, yes. There’s another way to use sound – to make up a variable capacitor.
In an ironic twist, the Soviet Union invented that to spy on the US – Leon Theremin’s The Thing (sounds like a comic-book villain, but is/was quite real, scary and really undetected for years, from 1945 to 1952) was the first RFID device, spy works or not. It worked like this: a resonant cavity sensitive to electromagnetic radiation becomes active only when a radio signal of a certain frequency appears, while a sensitive diaphragm acts like a part of a capacitor plate – every vibration picked up will produce changes in the distance between the plates, in effect making it a variable capacitor to power an antenna. It had no bloody power supply or active electronic parts and worked only when the comrades generated the correct radio signal in its proximity. Is there another way?
What if our device is not a radio receiver but a radio transmitter, it could be smaller and it could work in the dark and total silence, too. How do we do it? What else can we harvest? Electromagnetic radiation. Anybody think of wireless chargers? Oh yes. Those. You know what else works like that? RFID sensors, those things shops put on clothes so they won’t be shoplifted. How does that work? When radio waves (which are a part of the electromagnetic spectrum) hit an electric conductor (an antenna), they generate a small voltage in it – which in turn will power a small circuit. Therefore, hitting the antenna with a radio wave of a certain frequency can power a small circuit that can produce a radio signal – only without an amplifier the range of that signal will be quite small. Yet, it’s still a way to make a radio transmitter, ain’t it? RFID tags, sensors that activate on specific things ranging from the presence of bacteria to sounds or smells – those are real. That’s how they work.
There you go – one question, 5 answers, all of them correct. There are even more ways to make something work without a power source – like where exactly would you put it? What if you put it on your wrist? Could your hand motions power a small battery by harnessing gravity and motion through a spring that stores mechanical energy? Of course, that’s how mechanical watches work, that spring acts as a battery. Now we got 6 answers. See? Science. There’s more, but too much of a good thing can be wonderful.
The difference between just using something and knowing how it actually works is like the key to the presidential bathroom. It unlocks possibilities, it opens doors, stuff like that. It’s important in every way because how else could we determine what is the most efficient way of building something? We’d still be using donkey power to haul luggage, I think. If all you have is a hammer, everything sort of looks like a nail. Lateral thinking is a big part of a scientist’s bag o’ tricks, just like whiskey or, well, a Bloody Mary.
Magic is not about things popping up into existence or beautiful assistants levitating their skirts up, it’s the art of fooling every single sense we usually rely on. It’s the art of making people see reality in a different way, in a Picasso-esque setting. Magic is designed to offer functionality without noticeable limits, just like science. I don’t think any other disciplines are more connected or more alike, though I may have a slight Eiffel Tower sized bias here.. Everything we see around us is the work of human intellect in bending technology to fit design. It’s not Ford’s world anymore, to tell customers they can have a car of any color they choose, as long as that color is black. It’s magic.
Any sufficiently advanced technology is indistinguishable from magic – Clarke’s third Law.