MacGyver Science: Barn Find + Engine Oil + La Punzonatura + Lab Rats + Tachometer

DIY Epoxy Putty

MacGyver, Riley, and Bozer are on a ship — and that ship is in trouble. It’s sinking. In order to seal some leaks, MacGyver makes some epoxy putty. He uses: olive oil, sand, epoxy resin, and shampoo.

He’s actually trying to make something like this epoxy putty.

Here is a DIY putty (clay) that is similar.

But the bad news — it doesn’t work. Something went wrong.

What Went Wrong?

MacGyver is trying to figure out why the epoxy putty failed. If you’ve watched the show, you know the reason. He’s losing feeling in his hands. When he was mixing it, he couldn’t correctly feel the texture and the temperature. Yes, epoxy gets hot when it reacts.

MacGyver thinks that it’s possible he miscalculated Gibbs free energy. So, what the heck is Gibbs free energy? When you have a thermodynamic reaction, the Gibbs free energy is the amount of energy that you can get out of the thermal energy in the reaction. Yes, that’s that the full story — but it’s enough for now. I’m just happy this line made it in the show.

Airbag Lift

Yes, airbags are crazy awesome. Just think about how fast they have to open in order to be useful in a crash. It’s just amazing if you think about it.

MacGyver needs to get the old car towed out of the gun fight. But you can’t tow something without jacking it up first. So, Mac uses two airbags under the car to lift it up. “That’s never going to work…”

Image: CBS MacGyver

Once the air bags lift the car, MacGyver quickly slides a toolbox under it so that he can then connect the tow rig.

Could this actually work? Of course. Lifting just one end of the car means you don’t have to lift the whole weight. Also, you would be surprised how much energy is stored in these life-saving exploding bags.

Please don’t try that.

Actually, one of the early ideas was for MacGyver to make an exhaust bag jack. The idea is to use the exhaust from the car to inflate a bag to lift the car. Oh, it’s real.

Of course, this wouldn’t be fast enough to work in the middle of a gun fight. The air bags are quicker.

DIY Oil Slick

It’s the classic “Spy Hunter” vs. “James Bond”. I’m a huge fan of Spy Hunter — I’m talking about the arcade version, not the one on the Nintendo. But anyway, the idea is to let some oil out of the old car so that the guys in pursuit of them will crash.

But would this actually work? Maybe this would be a great thing for the MythBusters to test. Oh wait, they did.

When a car takes a turn, it’s velocity changes direction. Since the velocity changes (just the direction), that means there is an acceleration. Turning in a circle even at a constant speed is an acceleration.

Since the car has to accelerate for a turn, you need a force on it. In just about every case (at least for normal cars) this force is from the friction between the tires and the road. When you add oil to the road, you decrease the amount of friction so that the car can’t effectively turn — and it slides off the road.

We often think of friction as a bad thing — but we couldn’t get around without it.

Fixing an Alternator Belt

It’s not a huge fix — Desi uses MacGyver’s belt to create a new belt for the car. OK, I just want to include this video of these guys fixing up a car from junk. It’s awesome.

Finally, push starting a car. Normally you have an electric motor that rotates the engine so that it can start the combustion process. But if the battery is dead (or the starter motor is bad), you need another method to get it cranking. That’s what you do with a push start. The first step is to get the car moving (by actually pushing it). After that, you release the clutch and engage the transmission. This turns over the engine so that it starts. Yes, it only works for a manual transmission (although someone told me you can do it on an automatic car — but I don’t believe it).

Car Wrap

Mac and Desi use some vinyl poster stuff to wrap the car (for a disguise). But check out this nice heat gun to warm up the plastic so that it shrinks to the car.

Image: CBS/MacGyver

It’s just an electric heater inside a trash can-tube with a fan on the end. This will blow the hot air onto the vinyl. It’s basically a giant hair dryer.

Blood Pressure Gauge

MacGyver needs to keep his blood pressure down to prevent further problems with his hands. But that means he needs a way to monitor his blood pressure.

The normal method uses one of those inflatable cuffs that they put on your arm. By adjusting the pressure of the cuff and listening for a pulse, you can determine the blood pressure. Of course this method won’t work for MacGyver as he’s moving around.

There is an indirect method to measure the blood pressure — you can estimate blood pressure using a pulse oximeter. A pulse oximeter measures the amount of oxygen in your blood. It does this by shining a light through your finger. The opacity of your blood changes based on the amount of oxygen in it.

Here is a DIY pulse oximeter.

OK, that’s a fully digital version. But MacGyver is going to make his a little different. He’s going to use a motor cycle tachometer as a voltmeter. Oh, technically this a MacGyver-Desi build since he can’t use his hands.

Image: CBS/MacGyver

OK, I tried to make a video showing that a tachometer is basically a voltmeter — and it just sort of worked. But here it is anyway.

Actually, I really like how the final gauge looks on MacGyver’s wrist. It’s sort of steam-punk looking.

Image: CBS/MacGyver

Arresting Cable Car Stop

How do you stop a speeding car without destroying it? How about something like an arresting cable for planes landing on an aircraft carrier.

Here is the cable with the hook for the car to catch.

Image: CBS/MacGyver

The cable is then run around the rear tire of the SUV that’s jacked up. When the car hits the cable, Desi can apply the brakes to control how much cable is released. This will allow the car to stop over a longer distance with a smaller force (so it doesn’t get destroyed).

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

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