MacGyver Science: C8H7ClO + Nano-Trackers + Resistance + Maldives + Mind Games

Explosive Pipe

Image: CBS/MacGyver

Mac and Riley need to escape from a server room. Bozer finds an old exit that’s covered up by a wall — but MacGyver needs to blow up the wall. He takes two cans of disinfectant and jams them into a short segment of pipe. There’s also two wires in there to provide a spark.

When a voltage is applied to the two wires, it makes a spark and this spark ignites the mixture of spray and air. Boom. This is your basic version of a potato gun — but without the potato.

Since both ends of the tube are sealed, the thing just blows up. Yes, the same thing can happen with a potato gun — so be very careful.

(Riley channeling her inner Jack by quoting Star Wars)

Radio Detector

Image: CBS/MacGyver

MacGyver needs to see if there are some tracking devices in a person before he talks to her. He builds this device from a PA speaker.

OK, so if you want to look for a transmitter it safe to assume it’s radiating some type of electromagnetic waves. All electromagnetic waves (visible light, radio waves, x-rays) have both an oscillating electric field AND an oscillating magnetic field. Often times it’s easier to detect the electric field oscillations, but it’s possible to measure changing in magnetic fields also.

The key here is to use a coil of wire. When a changing magnetic field passes through the coil, it will induce an electrical current. It’s this current that you could detect. However, the induced current is fairly small. It helps if you have an amplifier — that’s exactly what the loudspeaker does.

But wait! You can actually build your own changing magnetic field detector with a loop of wire and a speaker. Check it out.

Dealing With Tear Gas

There are different types of tear gas, but one of them is C_8H_7ClO (the 8 and the 7 should be subscripts so I used the underscore). This is the chemical formula for phenacyl chloride. It’s not actually tear gas — it’s worse than tear gas but it basically does the same thing.

So, what could you do to a tear gas launched into a crowd? Well, you could cover it with a traffic cone than top it off with a cloth and water. That’s exactly what real protestors do.

That’s why I love this hack — it’s completely real.


OK, in the title it’s nano-trackers. But that’s still “nano”. The name comes from the size — around a nanometer. One nanometer is 10^-9 meters. But what about something bigger? I mean, if these nano-trackers measure stuff AND send it out signals then they have to be bigger.

Well, what’s something that you could inhale that’s bigger than a nano-bot? How about something like a drop of stuff from a cough? Yeah, like COVID mouth-stuff. Those can be over 100 nanometers — that’s why a face mask can block these droplets and you can still smell some molecules like sulfur dioxide from a fart. There, I said it.

We don’t really have real nano-trackers like this (yet), but they are at least plausible at some point in the future.

Thermoelectric Devices

How do you provide power to a spacecraft that’s far from the Sun? You can’t use solar power and a battery won’t last long enough. One option is a TEG (Thermo-electric generator). The TEG uses a radioactive source that gets hot. Then you put an interface of two different metals together with one metal on the hot side and one on the cold. Boom — that’s it. The temperature difference generates an electric current.

Here is a very basic TEG that I made.

Photo: Rhett Allain

But what does this have to do with nano-trackers? The TEG is a lot like other devices (electric motors, speakers, LED lights) — they can both create an electrical current AND be driven by a current. If you take that same TEG and run current through it, it will produce a temperature difference. When used this way, it’s called a Peltier cooler.

OK, back to MacGyver. How can they disable the nano-trackers? Well, normally, the outside of your body (we call this the skin) is cooler than the inside. That’s why you put a thermometer in your mouth (or some other place) to see if you are sick. But what if you made the inside colder than the outside? In that case, you could change the direction of current flow in the nano-trackers and get them to reset. I know, that seems like it’s a stretch — but remember, these nano-trackers aren’t real anyway.

Physics faculty, science blogger of all things geek. Technical Consultant for CBS MacGyver and MythBusters. Former WIRED blogger.

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