# MacGyver Season 1 Episode 17 Science Notes: Ruler

Propane tank flame thrower

Take a propane tank and bicycle tube. Cut the bike tire to make it a hose and connect it to the propane tank. Use a road flare to light the gas—boom. There is your flame thrower.

Oh but wait. It’s just a dream. Bozer’s dream. The flame thrower wasn’t real anyway.

Listen in on a landline phone

Who uses a landline now anyway? Oh well. They want to use a landline then it’s possible to listen in. Actually, this isn’t even that difficult. Check it out.

Here is another version.

You just need a capacitor and maybe an inductor. You could grab these from a radio or something like that.

But wait. I made a mistake. While going over this hack, I said something like this:

“Yeah, this is pretty easy. Just get the capacitor and earpiece (or radio) and then tie it into the wiring box”

Here’s what that looks like.

I just want to point out this small mistake (that you would never notice) just in case you saw it. You don’t actually “tie” the lines—that’s just a term we use in circuits to mean “connect”.

There’s a bomb in the truck. Where should you park it so that no one gets hurt? Yeah, this is a tough calculation. However, tough has never stopped MacGyver before and it won’t stop him now.

Here is my rough calculation and explaination.

Bombs are complicated. But usually it is the pressure produced by the explosion that will get you. We can come up with some pretty useful models to calculate their impact. First, there is the Hopkinson-Cranz Scaling Law (this is a real thing). With this law, the acceptable distance can be calculated based on the explosive weight.

$\mathrm{Range} = (z)(\mathrm{weight})^(1/3)$

In this expression z is a factor that depends on the type of distance with 14.8 being the distance factor for a public traffic route. That means that 2 kilograms would need 18.6 meters (60 feet).

Infrared face jammer

OK, it doesn’t actually jam your face. That would be weird. MacGyver wants to prevent the security cameras from recognizing their faces. So he takes some infrared TV removes and pulls out the IR LED lights. Normally these flash on and off so that the sensor on the TV can “see them” but humans can’t.

He mounts these IR LED lights on some sun glasses with a battery to power them. When a security camera sees the face, it just gets blinded by the IR light since many video cameras can also detect IR.

If your phone camera doesn’t have an IR filter (most now do) then you can actually see the light flashing on a TV remote by pointing it at your phone.

Oh, so this could really work. It just depends on the type of video cameras. Some people even put stuff like this on their car license plate so that police cameras can’t see them.

Car jacking

How do you open a locked car door? One way is to jam a wedge into the door. This will pull the door out just a little (by bending it) so that you can get a stick in there. The stick then can be used to push the “lock” button.

In this case, MacGyver uses something for the wedge—maybe a shoe horn or a door stop. Then a monopod is extended to click the lock button.

DIY soldering iron

You might have missed this one. But as MacGyver is building his stuff for the last mission, he needs a soldering iron. He takes the heating element out of a hair dryer and connects it to some stuff. That works.

Fake noses

Need a disguise? How about DIY latex to make a nose? Yes, this seems plausible. Here’s how to do it.

MacGyver makes a quick circuit board that can crack a keypad by using a brute force method that goes through all the combinations. This is from a different episode, but it’s the same idea.

If you want to play with one yourself, here is an online version of the code.

Well, it’s just a radio. MacGyver needs a speaker and a transmitter. Really, a radio transmitter is essentially the same thing as a radio receiver—OK, not really but sort of.

Instead of going over the way MacGyver did it, how about a real actual radio you could build yourself? Here is a spark gap transmitter from simple parts (and awesome).

Here is a more detailed explanation of the spark gap transmitter from one of my WIRED posts.

# MacGyver Season 3 Episode 14 Science Notes: Father + Bride + Betrayal

Hotel door break in with a coat hanger

MacGyver uses a series of coat hanger wires to build a device that opens a hotel door from the inside. It’s basically a long wire that goes under the door and pulls down on the handle from the inside. Here is a video of what that looks like.

Don’t break into other people’s hotel rooms. That’s illegal. You have been warned.

Oh, but that’s not the best part. MacGyver says this is really about torque. Yes, that’s true. You need to exert a torque on that inside handle to get it to turn.

Wait. The real best part is when Riley says “It means physics is awesome”. Yeah it does.

Thermite toothpaste

So the bad dude that is turning himself in has a special safe. If you try to break in—thermite melts the stuff inside. Yes. Thermite is real and thermite is awesome. In fact, here is an older video where we set off some thermite as a chemistry demo.

We need to do this again.

OK, but could you make thermite into a paste? You might be thinking “oh, if you put the thermite in toothpaste, it won’t get as much oxygen for the reaction.” Good idea—but surprise! Thermite has its own supply of oxygen. You can even get a thermite reaction to work underwater.

Really, the only issue with toothpaste is that you don’t want to get the thermite stuff (particles) too far apart so that they can still interact with nearby particles.

Spray can flame thrower with a bonus

Yes, we pretty much all know that if you get a spray can and shoot it into fire you get a mini flame thrower. Oh, I’ve never done this myself but I know a friend of a friend that did it that one time. I’m sure you’ve never tired this either.

But what about the bonus? If you get any type of fine powder, it also explodes (that’s the powdered sugar part that adds to the flame thrower). Yes, when particles are very small and very spread out—they can explode.

Here is an example from season 1.

Cyanide detection

It turns out that there is a fast method to test for cyanide poisoning (which can happen from certain fires—not just for spies).

Here is an article on how this works— https://phys.org/news/2015-03-cyanide-poisoning-seconds.html.

The basic idea is to get the cyanide the cyanide by mixing the blood with both an acid (muriatic acid and/or vinegar) and a base (like baking soda). Add this to a fluorescent agent like a detergent and then look at it with an ultraviolet light. If it glows—it’s cyanide. At least this is plausible.

Cyanide antidote

For the antidote, MacGyver is basically going to make sulfanegen—an experimental cyanide antidote. Yes, humans do indeed build up a sort of tolerance to cyanide since it’s a natural element in many fruits and stuff. Here is my half-plausible method.

• You need sulfur. You can get this from match heads. Yes, that’s true.
• Acid—cleaning supplies.
• Hydrogen peroxide
• Blood. Yes—that might be gross, but you do need that.
• Heat it up and filter it with a coffee filter.

Now, how do you get it to Riley? You could use an IV—but a nasal spray should work too. This is why they give some kids the flu vaccine with a nasal spray.

Don’t actually try to cure someone with this recipe.

Finding the real bad person with interference

MacGyver uses the interference sound from Riley’s radio when she is attacked to figure out that someone is the bad person. Basically, someone had a device that interfered with the radio.

If you had a mobile phone (we didn’t call them smart phones because they weren’t that smart back then) in 90s or early 2000s, then you know what happens when they get near a speaker.

It’s entirely plausible that a medical alert bracelet could do this. In fact, medical equipment often uses older technology because they don’t like to move to newer stuff until it’s been fully tested.

In fact, there could be some type of extra interference caused by the taser and the medical bracelet. That’s what MacGyver wants to reproduce and detect. All he needs to do is to reproduce the taser signal and create an audio output so that he can “test” different people and find the baddie.

# MacGyver Season 1 Episode 13 Science Notes: Large Blade

Tarp restraint

This is sort of like a straight jacket made out of a tarp and a belt. I wonder how long this would last—but it’s still a classic MacGyver hack. This blog would probably be better if I included pictures. Oh well.

Space blanket as chaff

A space blanket is basically a thin mylar sheet. It has a nice property in that it reflects infrared radiation. The idea is that you cover yourself with this and when your body radiates infrared light, it reflects it back to your body.

Can you use this as a countermeasure against a ground to air missile? Maybe. Of course there are two types of missiles. There is the heat seeking missile and the radar missile. For the heat seeking missile, it is guiding by the giant infrared source—the engine of the aircraft. It’s a least plausible that this space blanket could block the infrared light from the helicopter enough to confuse the missile. Possible.

If the missile is radar guided, then you can block the radar that comes out of the missile. This is the idea behind chaff (a real thing). It’s basically thin strips of metal that fall in the air behind an aircraft. The metal spreads out and can make a large radar reflection such that the missile thinks it’s a target.

Would a space blanket work? It’s possible. Really, you want metal—but this might work at least a little bit.

Splint and crutch from helicopter parts

Classic MacGyver stuff here. Nothing else to say.

Clean water from a tree

Can you get clean water from a tree? It seems like this is legitimate.

Dried wood as a desiccator

This seems like a plausible way to dry out a wet phone. It would take some time though.

Swiss Army Knife as a signal mirror

MacGyver uses the blade on his knife to attempt to reflect sunlight towards a rescue helicopter. I’m pretty sure this would work.

As a side note—I’ve been thinking about the brightness of light reflected from a mirror (for another project). It seems like this is fairly difficult to calculate. Perhaps the best way is to just experimentally measure the brightness of reflected light. I guess I will do that at some point.

Tree sap and a battery to start a fire

If you want to use a battery to start a fire, you need an electrical conductor. This allows electric current to flow from one terminal of the battery to the other. It’s this electrical current that can make things get hot—hot enough to catch on fire.

So, the battery part is good. What about the tree sap? Yes—apparently, it is indeed a conductor. There you go, a fire.

Distance to lightning strikes

This is another reminder. I should write a post about how to estimate the distance to a storm. The short answer is that when lightning strikes it produces both light and sound. The light has a super high speed, but the sound is just fast (not super high fast). This means that the light gets to the observer first. By counting the time between the “flash” and the “boom” you can estimate the distance.

Creating a homemade capacitor to store charge

Here is the short version: MacGyver makes a DIY electrical capacitor (a Leyden jar) to get some electrical charge from a lightning storm. He then uses this to power the satellite phone.

The Leyden jar is totally real. Honestly, I was surprised at how well this worked. Check it out.

Finally, you can make something like this yourself.

Zipper as an wire

MacGyver uses the zipper to make a complete circuit from the battery to the sat phone. Would this work? It’s tough to say. In order to get an electric current, you need a closed circuit with a conductor the around the whole path.

Parts of a zipper are clearly conductors (the metal parts). However, if there are gaps between the metal, then it wouldn’t work. If you zip the zipper, there should be contact—at the very least, this is plausible.

# MacGyver Season 1 Episode 11 Science Notes: Scissors

Kill computer stuff with a transformer

How do you get a hacker to do what you want (or tell you want you want)? You start destroying all his electronic stuff. In this case MacGyver uses a transformer to zap some computer equipment.

What is a transformer? It’s basically a coil of wire connected to an AC voltage (like your wall outlet). This AC outlet makes an alternating current in the coil that produces an alternating magnetic field.

Now for the second part of the transformer—another coil. Yes. If you have another coil of wire, the changing magnetic field from the first coil will induce and electric voltage in the second coil. By changing the number of turns in the two coils, you can either increase or decrease the original voltage—or perhaps you could say you “transform” the voltage. Get it?

OK, so MacGyver takes this transformer. With it, he creates a high voltage. The voltage is high enough to make a spark—this is indeed possible.

Next question: how does this spark kill a computer? Well, it’s not the spark but rather the electric current. If you get extra electric current going through the computer stuff, you can destroy those super tiny transistors. They weren’t meant to have much current. Without the transistors, you are pretty much a plain electric toaster.

Scissor Extenders

MacGyver needs to cut through a cable. It just so happens that this cable is choking someone—so he needs to move quickly. Of course he has scissors on his Swiss Army Knife, but he can’t push hard enough to cut the cable.

This is where the scissor extender comes in. MacGyver gets a long stick and adds it onto the end of the scissor handle. With this long handle, the same pushing force can create a much larger torque on the scissors (torque is the product of force and lever arm). This larger torque is enough to cut through the cable. It’s just like those super long handle sheers that you can use to trim tree branches or those bolt cutters that you can use to cut a chain.

OK, there is one small problem here. One stick might not be that helpful. If you have one long handle and one short handle, then you would have to apply the same torque on the short handle. That would be pretty tough.

Hack a car

This isn’t a “Mac Hack” —but I am going to talk about it anyway. There is a program that can hack into cars and take them over. Sadly, this is partially true. Check out this video from WIRED in which some hackers remotely stop a Jeep. Scary.

Could this be used to take over a nuclear submarine? Well, probably not.

Air Raid Siren

This is classic MacGyver. He creates an air raid siren out of PVC pipe and an AC condenser fan. It would probably work.

I was going to build one of these and make a video, but I didn’t. Here, check this one out instead.

RFID range extender

So, the guys want to use an RFID badge to access a security level in an elevator. MacGyver builds a DIY range extender. This is fairly plausible, but I won’t go over all the details. Instead, I will just share this paper.

The whole building is a Faraday cage. The basic idea is to create a grounded metal enclosure so that electromagnetic waves can’t penetrate. That means, no phone signals and no wifi outside of the building.

Here is an example of a Faraday cage (from a later episode, but who cares—right?).

Spoof GPS

There is a missile flying towards the USA. That’s bad. MacGyver builds a parabolic dish to act as a GPS spoofer. This could basically work. The signal from the dish could be stronger than the one from orbit and trick the missile into going the wrong way.

Of course, there is one small problem. If the missile is 3000 miles away, you couldn’t get direct-line sight of it unless it was super high. Well, I guess these missiles do go pretty high. Still, it would be hard to aim it.

It’s still plausible.

Artificial snow

How do you make fake snow? One way is to shoot water out of a nozzle at high pressure. When the water leaves the nozzle, it expands and cools off. If it cools off enough, it will freeze and make something that is like snow. These things are real.

But can you make snow above the freezing point? Oh yeah.

# MacGyver Season 3 episode 12 Science notes: Fence + Suitcase + Americium-241

It’s not a super Mac-hack, but it works. The only thing MacGyver does is to put a toothpick in place a grenade pin. It only works for a little bit before the grenade explodes. However, the physics discussion is pretty good. Let’s go over some of the terms.

• Tensile strength. This is essentially the maximum force a material can withstand when being pulled apart. Just imagine a rope—how hard can you pull on the rope before it breaks. That would be the ultimate tensile strength. Yes, wood has a pretty high tensile strength.
• Compressive strength. How hard can you squeeze the thing before it fails? Something like concrete has a very high compressive strength, but not so much with tensile strength. Wood could have a good compressive strength if it’s wide and short. Long skinny boards of wood tend to buckle.
• Sheer strength. This is the maximum force an object can withstand when two forces are pushing in opposite directions but not directly at each other. Think of scissors.

What is a dirty bomb?

This is another non-hack. However, I just want to describe the difference between a nuclear bomb and a dirty bomb. A nuclear bomb uses a nuclear reaction (usually started with conventional explosives) to make a massive boom.

The dirty bomb is NOT a nuclear explosion. Instead, it uses conventional explosives to spread radioactive material around. It’s dirty.

Electromagnet

MacGyver builds a strong electromagnet to move a bolt inside a locked door. Yes, this is possible. You would need a strong electromagnet—that means high electric current and thus thick wires. You also need a fairly beefy battery to get this much current.

Oh, one possible problem. If the bolt is ferromagnetic (steel) and so is the door, then it’s going to be difficult to get that bolt to move. However, if the door is aluminum or some type of non-ferromagnetic material then this would work.

Wall walk

There are two methods to get over the pressure sensitive floor (they end up not using this though). There is a wall-walking stilt method and a rolling sled method. Both have the contact point with the wall at an angle—this is needed in order to work (because of physics).

Let me just start with a setup that would only barely work. Here is a view of a person using completely horizontal stilts along with the forces on the person.

The first problem is that the stick the reaches across the hall would have to fit perfectly. The harder it is pushed against the wall, the greater the frictional force. And it is this upward frictional force that balances the weight pulling down.

The second problem is with these horizontal arms. When they attach to the person, there is no upward force. This would be like trying to hold a rope with a weight in the middle perfectly horizontal. It won’t work.

Here is a better option.

This setup fixes both of the problems. The sticks can be longer than the hallway (and not fit perfectly) and there is now an upward component from the wall that helps support the human.

Mercury Switch

What is a mercury switch and how can you build something similar? Here, I made a video for you.

MacGyver uses some smartphones (as usual) to detect radiation from the dirty bomb. This is essentially real.

A smartphone camera has a sensor that is normally used to detect light. However, this same sensor can be set off by other types of radiation—like the stuff that is produced by radioactive stuff.

In order to actually detect this radiation, you need to block the light from getting to the camera—electric tape over the lens will do the trick.

But wait! There is a real project that uses normal human smartphones to detect cosmic radiation. Check it out—the CRAYIS Project. https://crayfis.io/

Rolling Tire Bomb

Yeah, mixing stuff and make explosions. The end.

# MacGyver Season 1 Episode 7 Science Notes: Can Opener

Let’s do it.

Ring of fire

MacGyver uses a fire hose to spray gasoline on the ground and then Jack ignites it with a bullet. It looks cool, but there are two problems. One small problem—bullets don’t make sparks (usually)—http://www.cracked.com/article_19781_6-stupid-gun-myths-everyone-believes-thanks-to-movies.html.

Oh, also gasoline doesn’t always burn that well.

OK, but gasoline CAN burn and bullets CAN make sparks—so this isn’t completely crazy.

Fixing an inhaler

MacGyver uses part of a plastic force to fix the part that pushes the release valve of a broken inhaler. This is exactly the kind of thing MacGyver would do.

Battery hydrogen bomb

OK, this is mostly real—but very awesome. Here’s how it works. If you put an electric current through some water, you can break the water into hydrogen and oxygen. In order to do this, you need the water to be able to conduct electricity. NEWS FLASH: pure water doesn’t do this. If you add some salt, water conducts just fine.

Now with the current going through the water, you get tiny bubbles. Bubbles on one electrode (I can’t remember which) are bubbles of hydrogen gas. The other set of bubbles on the other electrode are oxygen.

You can seriously do this on your own. It’s really not hard.

But how would you make an explosion? You can let the hydrogen and oxygen gas mix together—nothing will really happen until you get a spark to star the reaction between the two gases at which point BOOM.

So, in the case of MacGyver he wants to let the hydrogen gas collect at the ceiling. Yes, the hydrogen gas would rise but it’s also difficult to contain. Any tiny crack and it’s gone—but still, it’s a good idea.

What about the ignition? A spark will do. Yes, you can indeed get a spark from a fluorescent light. Especially from the ballast since it makes a high voltage.

Oh, one more comment. What about the 2 psi pressure difference? Is that possible? Probably. Would it knock the door off? I think so—especially if the pressure change is quick. Would it be bad for humans? Could be.

Morse code with the tail lights?

Totally legit.

Final breakout part 1: making liquid nitrogen

OK, this is a stretch. MacGyver uses a carbon dioxide fire extinguisher and some alcohol to make liquid nitrogen. It doesn’t say liquid nitrogen, but that’s what it is (from the air). Let me just show this video:

See. It’s possible. It’s not easy, it’s possible. What about the dry ice? Well, that’s another stretch. Expanding carbon dioxide from a compressed tank CAN INDEED make dry ice. In fact, that’s how we do it in chemistry sometimes.

Final breakout part 2: breaking steel

MacGyver takes the liquid nitrogen and puts it on some steel bars. The get super cold and breakable. The first problem: you would need a lot of liquid nitrogen to cool off the metal. But OK. The second problem—there really isn’t another problem. If you get it cold enough, I think it would work.

# My MacGyver Interview

I would just like to share this video (and then some comments).  This is from CBS KPIX channel 5 in San Fransisco.

• I was contacted a while ago by Sharon Chin from KPIX.  She was interested in doing a story on the science of MacGyver.  Actually, I’m not 100 percent sure how she knew I was the science advisor (actually, I’m the technical consultant)—I guess that’s why she’s a journalist.
• We picked a day for Sharon and a camera person to come visit me at Southeastern—we ended up with Halloween.  That’s just the day that worked.
• They arrived around 9:00 AM and we first recorded an interview.  After that, we went through probably 5 MacGyver builds.  It was tough recording all that stuff.  We had to do it multiple times to get the camera angles correct.
• After that, they visited my PHYS 142 class (you know, the one that’s on the chopping blocks).  They interviewed a student and then watched some of the class.
• Overall, things went great—but I was super tired afterwards.
• Super grateful to Sharon and KPIX for doing this episode.  It’s great to get some more publicity.
• Oh, one thing I try to make clear in the interview—I’m not responsible for all the hacks.  Credit goes to the awesome MacGyver writers.  They come up with some great stuff.
• Oh, double credit also to the editor for this video.  They must have had about 5 hours worth of video to get 3 minutes of air time.  Impressive.  I wouldn’t want to do that.
• The end.
• I don’t need this last bullet—but it’s here anyway.

# Fake or Not: Physics analysis of “Extreme way to shop for groceries”

Here is the video in question:

Looks too incredible to be real for me. That is when I start to question things. Is this fake or not? To answer this, I took a clip that showed a person launching a grocery item over the isle. This was a good shot to look at because it was *mostly* perpendicular to the camera view. I then used [Tracker video analysis (free) tool](http://www.cabrillo.edu/~dbrown/tracker/) to get x-y-time data for the flying projectile grocery. The scale was difficult, so I just guessed that the guy on the left was 5 foot 10 inches. Here is the vertical position data for two tosses.

A few things to notice:
– The plots are mostly parabolic. This is what you would expect from a real toss (air resistance would be small)
– The two tosses have essentially the same acceleration.
– The acceleration of these two tosses is in the ball park of -9.8 m/s2. Yes, they are not right on, but I totally guessed on the scale of the video.

So, from this, I think that shot is real. It is still incredible. Maybe they did this for like two hours to get it right. Maybe they just got lucky. Maybe they used the force and the force is strong in their family.

I was going to add an analysis of how off they could be on their throws and still make the “basket”, but I got lazy. Sorry. Maybe I will add that later.