MacGyver Science Notes Season 3: Episode 10 Matty + Ethan + Fidelity

Using a drone to lift a human.

OK, maybe this isn’t exactly a Mac-hack since he didn’t build it.  But can you use a drone to lift a person?  Oh yeah—this is real.

The basic idea of a drone is that it provides upward lift by “throwing” air down.  In order to conserve momentum, the downward force on the air is equal to an upward lift.  This means a couple of things:

• Faster air gives greater lift (because the air has greater momentum).
• Larger rotor areas give greater lift (because there is more air thrown down).
• The power required to hover is proportional to the air speed to the third power.  That means you don’t want to use fast air.
• Instead, you want big rotors with slower air.

Here is a post with a bit more explanation. But it is indeed possible.  Oh, the drone MacGyver uses could work, but it would be better if the rotors were a little bit bigger.

Cricket Ball Flash Bang

MacGyver tosses a ball into a room.  It then explodes with a flash to stun the people inside.  Is this possible?  Of course—it’s possible to even make your own flash bang.

Since the build for this device is off screen, let’s just leave it like that.  But it’s clearly possible.

Water Cooler Bomb

MacGyver takes a water cooler bottle and puts some stuff in it.  He then rolls it into a room and it explodes.  Again, stunning the people inside.  Yes, very plausible.

Instead of talking about explosives, here is a related demo using a cooler water bottle.  It’s the woosh rocket.  Check it out.

When you ignite the ethanol, it quickly uses up the oxygen in the bottle (because of the neck).  This causes a type of fluttering with the oxygen being used up and then entering the bottle.  It’s cool.

DIY Jaws of Life

OK, these aren’t actually jaws of life.  MacGyver gets some metal pieces to build a device to pry open a door using an electric drill as a motor source.

Here is a very rough sketch of how this would work.

OK, that’s not exactly the same—but it’s the same idea.  The spinning drill turns the threaded screw and pushes the metal bars apart.  The pivot makes the metal bars push apart on the other side.

Since the door side of the pivot is shorter than the drill side, the change in distance on the door side is smaller.  Why does this matter?  This matter because this is the way all simple machines work.  You can get a greater output force if you decrease the motion distance on the output.  That means on the drill side, there is a small force moving over a greater distance.

It’s the same idea as a basic lever. It’s how your basic garden sheers work too.

Here is something very similar (in physics at least)—a DIY floor jack.

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.

MacGyver Season 3 Episode 3

Transparent Explosives

Yes, this is probably real – http://www.guns.com/2016/10/21/army-working-on-high-tech-see-though-explosives/

Liquefaction of Sand

This is real.  You can make a simple version of this yourself.

Or you could make a crazy huge version like this.

Weather balloon pop

MacGyver needs to get a thermal camera down from a balloon.  The balloon (it’s not actually a weather balloon) is tethered down by multiple lines.  So Mac uses the jumper cables from the car and connects them to the car battery.  Then he connects ONE cable to the wire and the current causes the balloon to burst.

OK, let’s step back for a moment.  Remember that this is a show – this is not real life.  I just want to make sure we are all on the same page there.  So, there’s a small mistake here (you can blame me if you like).  In order to get an electric current from the car battery to go through the balloon, you would need to make a complete circuit.  One jumper cable connected to the line is a start, but there needs to be a path for the current to get back to the battery to make a complete circuit.

One way you could get this to work is to take another line going to the balloon and connect the other jumper cable to that one.  If you look close, it seems like the other cable isn’t connected to anything (in the show).  Of course, that mistake is better than connecting both wires to the same line.

This is sort of the same problem as this double spark in Iron Man 3.

Thermal camera

Yes.  Thermal cameras are indeed real.  Yes, the heat signature of an electric car would be different than an internal combustion engine car.  Actually, I need to see how hot they get in real life (electric cars).  I’m going to test this the next time I see a Tesla.

Oh, and here is an overview of seeing stuff in infrared (also called “thermal image”).

Just for fun, here is a visible and infrared image of me with a bag over my head.

X-Rays from a Vacuum Tube

MacGyver needs to find the transparent explosive.  One of the tools he needs for this is a source of x-rays.  This seems to be real – but it appears you can make x-rays from a vacuum tube, a lighter (the long kind) and a diode.

Here are the instructions from hackster.io (I need to build one of these).

There are so many cool parts of this hack, I could probably write a book on just this one thing – maybe I will write a separate post.  This x-ray device does the following:

• Uses a vacuum tube from an old radio.  Historically, the vacuum tube was used where transistors are used now.  These things are awesome.
• The lighter has a piezoelectric in it.  When you apply a pressure to these devices, it produces a voltage – the voltage can get high enough to make a spark in air which lights the gas from the lighter.
• When you connect the piezoelectric to the vacuum tube, you can make a super high voltage inside the tube.  This can accelerate electrons such that they crash into the other electrode.  This crashing electrons is exactly how you create x-rays.
• X-rays are just like normal visible light except that they have super small wavelength.  This can make them interact differently with matter.  For instance, they can pass through some materials (like human skin).
• What is the x-ray used for in this hack?  X-ray fluorescence.  This is essentially the same as glow in the dark (kind of) material except get’s “activated” with x-rays instead of other visible light.

Oh wait! I already have a video on x-ray fluorescence.

One final note.  In the show, MacGyver says something about shooting ions.  That’s not really what happens here.  X-rays are not ions.

Hydrogen balloon from a trash bag.

Can you fill a trash bag with hydrogen?  Yes.  Will it lift stuff?  Yes.  Could it lift a trash can?  Maybe…just maybe.

Here is my super short introduction to buoyancy.

Suppose you take a box of air – the box is 1 meter on a side such that the volume of this air is 1 x 1 x 1 = 1 m3.  Assuming there is no wind or breeze, this “box of air” will stay in the same location.  Since the box is at rest, the total force acting on the air must be zero.

OK, there is obviously a downward gravitational force on the air puling it down.  Yes, air has weight.  If something has mass, it has a gravitational interaction with the Earth.  Everyone likes to think of air as being weightless – but that’s probably because it has a low density and it’s normally “floating”.  But if there is a downward gravitational force on the air, there must be an upward force pushing to counteract the weight.  This upward force is the buoyancy force.

Since the box of air floats, we know the buoyancy force has to have the same magnitude of force as the weight of the air.

Now let’s suppose I take away that “box of air” and replace it with a sealed cardboard box (it could be a box made out of anything, but in my mind it’s a cardboard box).  The air around this box is going to interact with it in the same way as it did with the box of air (because air is dumb and doesn’t know any better). This means the cardboard box has the same buoyancy force as the box of air – it is equal to the gravitational weight of the air the box displaces – this is essentially Archimedes’ principle for floating stuff.

Oh, this buoyancy force is still the same no matter if the object is floating or not – it just has to displace air.  You can also do this with water or really any substance –  like pudding.  Not sure why you would float something in pudding.

But what if you want to calculate this buoyancy force?  In that case, you need to know the density of the air (which is around 1.2 kg/m3) and the local gravitational field (9.8 N/kg).  With that, the buoyancy force would be:

$F_\text{buoyancy} = V_\text{object} \rho_\text{air}g$

Finally, we are getting somewhere.  Now you can calculate the size (solve for V) of a balloon needed to lift a trash can.  If you want a simple estimate – you can ignore the mass of the hydrogen in the balloon (but it does indeed have both mass and weight just like the air).  I’m leaving the rest of this as a homework assignment for you.

MacGyver Season 1 Episode 5 Hacks

You know what would be great for these posts?  Images or gifs of the different hacks from the show.  Maybe someday I can add those.  For now, It’s just science and stuff.

Episode 105: Toothpick

Redirect a heat-seeking missile

I don’t like to use the “barely plausible” tag – but let’s be honest.  It’s going to be pretty difficult to redirect a heat seeking missile.  I guess it’s not impossible though.

A heat-seeking missile has an infrared receiver to look for “hot” objects.  Usually, this hot object is the jet engine exhaust for an aircraft.  So, for this hack, MacGyver wants to get the “attention” of this missile using a flood light.  Yes, these things get hot – but not jet engine hot.

Normally, a plain light would radiate energy in all directions.  Imagine this light as an expanding sphere with a particular radius.  Since the light must be even over the surface of this expanding sphere, the intensity of light decreases with distance.  The area of a sphere is proportional to the square of the radius – so this is where we get the “inverse square law” for light.

Of course the inverse square law means that a bright (and hot) flood light won’t do much if it is far away.  One way to fix this is to use a parabolic dish to refocus the infrared light – a spot light.  Yes, you can do this with a plain metal dish for infrared.

So, in the end MacGyver has an infrared source he can focus on the heat-seeking missile and perhaps get its attention.

Electric Razor Taser

(electric, plausible)

MacGyver makes a type of taser (not really a taser) out of an electric shaver.  The basic idea behind a taser is to shock a person with an electric current.  There are two types of current – there is direct current (DC) like the stuff that comes out of a battery.  This current just goes “one way” in a circuit.  Shocking people with DC current is a little bit more complicated.

The other current is alternating current (AC) in which the current constantly switches directions with some frequency.  In the US, AC current is at a frequency of 60 Hz.  Why does this matter?  It matters because if it’s a plug-in type razor then you already have AC current and it’s easier to shock someone with AC.

So, to make a plug-in razor taser you just need to take the main power lines coming into the razor and connect them to something on the front.  When a human victim touches both of these wires, the human becomes part of the circuit and gets shocked.

Don’t try that at home.

Toothpick gun jam

(mechanical, seems real)

If you don’t clean your gun, it probably won’t work.  A toothpick in the move-y part will probably mess it up.  Not a gun guy.  Oh, I don’t think this would make the gun misfire – just jam.  But you can see where the name of this episode comes from.

(physical, seems real)

So, MacGyver puts two smoke grenades in a jacket . Really, there’s not much to say here.

Metal Belt Buckle Attack

(physical, real)

In a classic MacGyver move – he uses his belt buckle as a weapon.

Fork Lock

(physical, real)

MacGyver uses a fork to lock a door.  This is a sliding door – but I was thinking of something like this:

Torpedo attack

(explosive, probably real)

MacGyver uses a train torpedo to attack a dude.  Not much to say here.

Thermite

(chemical, based on real thing, plausible)

MacGyver uses a pipe to hold the stuff – magnesium shavings and iron oxide shavings.  Boom – thermite.  Thermite is a chemical reaction that gets SUPER hot.  It’s actually pretty awesome but not easy to make.  You need to get the metal into a very fine powder.  But if you do that, here’s what happens.

Stopping a train

(electric, physics, partially plausible)

How do you stop a train?  One way is to mess with the DC motors.  Yes, most trains are diesel-electric.  They have diesel engines that power electric motors.  If it’s a DC electric motor, you can switch the polarity of the wires and the motor will rotate the opposite way.

This might not stop the train right away – but it’s a start.  Here is a demo you can try at home.  Oh wait – I can’t find the video.  Well, here’s what you do.  Get a battery powered toy car with a motor (a cheap one).  Switch the direction of the batteries and the car will drive backwards.

I found the video.  Here it is.

MacGyver Season 1 Episode 1 Hacks

Hello and welcome.  I should have started this a long time ago, but it’s never too late.  In this series, I am going to go through each episode of MacGyver (the reboot) and describe all of the science in the “Mac Hacks”.

Oh, I guess I should mention that I am the Technical Consultant for the MacGyver show – but maybe you already knew that.

I will also give a score for each hack.  Here is the grading scale.

• Real. This is a real hack that would probably work.
• Very plausible. This is based on real science, but might not work – it might require some luck to get it to work.
• Plausible. Also based on real science, but it probably wouldn’t work as shown.
• Iffy. Yeah, this probably wouldn’t work in real life and it might not even be based on real science.

Of course I will start with Season 1 Episode 1: The Rising. Note: I didn’t really work on this episode.

1) Finding Fingerprints.

(Very plausible, forensics, biology)

MacGyver uses tailpipe soot to sprinkle on a glass to find fingerprints.  He then uses tape to capture the print. I don’t really have much to say about this hack

2) Electromagnet.

Getting the battery from a stud finder and stripping a wire and coiling around iron to make an electromagnet .  He then uses this to interfere with a radio.

Now for an explanation.  Ok, electromagnets are real.  An electric current does indeed make a magnetic field.  You can make a stronger magnetic field by forming a wire into multiple loops.  One quick note – you can’t use bare copper wire.  The wire has to have insulation around it – like rubber or enamel (a thin coating in magnet wire – used for motors).  If you add a ferromagnetic core (like iron) inside the loop, the magnetic domains in the core will line up with the magnetic field due to the loop and create a stronger magnetic field.

What about jamming a radio?  Radios send signals (and receive) using electromagnetic waves.  These are oscillations in both electric and magnetic fields (way more complicated than just one sentence – but that’s good for now).  So, can a magnetic field interfere with EM waves?  Not really.  What you COULD do is make an oscillating magnetic field.  This would in turn create an oscillating electric field and its own EM wave.  If the frequency of this EM wave is the same as the radio – boom – you have interference.

There are ways of making an oscillating magnetic field – but I will leave this for now.

3) Tricking a hand scanner.

(iffy, forensics, biology)

Put dust on a hand scanner and then blow off the excess.  The remaining dust sticks to residual oils.  Mac then covers over with his shirt.

This hack is fine for a show, but if these hand scanners were that easy to fool – wouldn’t everyone be doing it?

4) Paperclip picking handcuffs.

(plausible, physical hack)

5) Smoke bomb.

(plausible, explosive, chemistry)

Mixing tinfoil, muriatic acid and ammonia to make smoke – yes, this makes lots of smoke.  Putting it in a closed bottle would be a bad idea though – it would probably create a small explosion when the pressure inside the bottle got too high.

6) DIY Bola.

(plausible, physical hack)

Mac builds a bola from a soda can filled with asphalt, and cut in half.  The two halves are closed up and tied together.  Nothing super special about this – but I am a big fan of these types of hacks where he actually builds some physical thingy.  It feels like the fundamental essence of MacGyverisms.

7) Disable aircraft landing gear.

(plausible, physical hack)

MacGyver uses his swiss army knife (SAK) to disable the retracting landing gear of a plane.  This seems very plausible.

8) Hot wiring a circuit.

(plausible, circuit)

Mac does some type of hot wiring – not sure what’s going on here.

9) Disable a bomb.

(very plausible, circuit)

I mean – MacGyver was a bomb guy in the army.  I’m sure he could figure out some way to disable this bomb.