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MacGyver Season 1 Episode 3 Hacks

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Welcome to my continuing series on the science behind MacGyver hacks.  Really, I should start changing the blog title so that it includes the episode name – this one is titled: Awl.

Another note: I was going to wait until the MacGyver Season 1+2 DVD came out so that I could rewatch each episode.  I don’t want to wait, so I am just going from my original notes for this episode.  Let’s get started.

Episode 103 Awl

Body bag with fire extinguisher for jumping out a window

(slightly plausible, physics, forces)

MacGyver and Jack need to escape a burning building.  They grab body bags with fire extinguishers and then jump out of a 3 story building.  On the way down, they inflate the body bags with the extinguisher to make a cushion to land on.  That’s the hack.

Actually, I already wrote a whole blog post on this hack – here it is at wired.com. But the short answer that this is based on some real stuff.  Increasing the distance over which a human stops decreases the acceleration.  Smaller accelerations are better than higher accelerations.  Oh, filling up the body bag on the way down is the best so that the CO2 won’t have time to escape.

Still, I wouldn’t try this at home.

WiFi Jammer

(very plausible, light, electronics)

MacGyver uses one of Riley’s wireless cameras to make a wifi jammer.  There are two important parts to this hack.  First, he needs to do something to the camera so that it sends out some type of signal to “jam” other wifi.  He uses a cigarette lighter to solder wires.  I’m not sure that this would work – but it’s at least plausible.

The next part is to add a directional antenna to the wifi camera so that the signal can be sent to the house (that needs to be jammed).  MacGyver builds a directional antenna to add over the existing antenna using a soda can.  This is real.

In fact – you can build this yourself, here is how.

Thermal Camera Note

(maybe, light, infrared)

This isn’t really a hack – but there is some science.  The team uses a thermal camera to watch the dude they are spying on enter his pin code.  The keys he pressed stay warm and they use this to figure out his alarm code.  This part is real – in fact, there was a story about people using thermal cameras to steal pin codes.

Now, there are two possible problems in this “hack”.  First is the glass.  Actually, I can’t recall how it happens in the show – but I advised to be sure to look through an open window.  Infrared light doesn’t go through glass.  Even though infrared is still a type of electromagnetic wave (just like visible light), it interacts differently with matter.  It doesn’t go through glass, but it CAN go through some plastic – here is more details.

The other issue is resolution.  Infrared has a longer wavelength than visible light.  This means that it’s more difficult (but not impossible) to see small details from far away.

Bullet Vent Seal

(plausible, biology, medical)

A guy has a bullet wound.  MacGyver uses a drivers license and tape to make a flap.  This flap allows gas to escape – but not other stuff in.  That’s all I have to say about that.

Headrest Smoke Bomb

(plausible, fire)

Mac stuffs some paper into a car’s headrest and lights it on fire.  It makes smoke to act as a smoke screen.  It probably wouldn’t work very well – but it would make some smoke.

Hot antifreeze disinfectant

(slightly plausible, medical)

If you want to do some medical stuff in the back seat – you need a clean environment (or the patient will die from infection).  In this case, MacGyver uses hot radiator fluid to wipe down the area.  Hot stuff usually kills bacteria – but this probably wouldn’t work.

Windshield wiper pump for gross stuff

(plausible, medical, electrical)

MacGyver basically uses the windshield wiper pump to suck stuff out of the guy’s lungs.  I don’t want to talk about this.

Improvised syringe

(plausible, mechanical build)

This is just putting stuff together.

Soda bottle gas mask

(plausible, mechanical build)

Cutting a soda bottle (plastic) so that it fits on your face is pretty straight forward.  Filtering out stuff is harder.  In this case, the filter is just wet newspaper.  This would filter out some stuff – but just smoke and dust and things.

Refrigerant gas attack

(it’s a stretch, chemical)

Mac uses refrigerant as a gas attack – not so sure about this one.  It’s clearly bad to breath in – but it would probably take quite a bit in a small space to knock someone out.

A Cave Diving Story

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I want to write about some things that happened in the past – mostly so I don’t forget.  In this case, I’m going to describe a particular cave dive that sticks in my mind.  Now, there is a warning.  This might not be exactly what happened – but it might also be true.  It’s probably the way it happened.  Let’s begin.

In case you aren’t familiar with cave diving, the main idea is to explore a cave that is completely underwater.  You start outside the cave and you are already underwater. This is not spelunking – this is cave diving.  We mostly went into springs in the panhandle of Florida – that was our roaming territory.

Just for fun, here is a picture of me with my cave diving gear.

Please don’t complain about the setup.  This was a picture from my cave diving class.  I learned quite a bit after this and changed things up – but still you can get an idea of what it was like.  That was my friend’s van that we used to drive to different caves – it was pretty sweet.

Ok – now for this one particular dive.  I am pretty sure this was at Twin Cave.  Twin Cave is in the middle of Merritt’s Mill Pond in Marianna Florida.  The only feasible way to get here is with a boat (unlike most cave diving in which you just walk into the water). It’s called “Twin Cave” because it has two entrances right next to each other (underwater).  If you have a boat, you can use a tiny little wood platform connected to two trees to set up stuff.

My dive partner (Trey) and I hitched a ride with Pat Watson.  He had a little john-boat and ferried us to the cave.  He then went back and picked up two more divers – Pat was teaching them how to cave dive and this was one of their “check out dives”.  Oh, I should add that at one point there was so much stuff in that little boat that it was barely above water.  One tiny wave and I think the thing would sink.

Now for the dive plan.  Go into Twin Caves and get into the lower levels.  In this case, we would use diver propulsion vehicles (DPV) to get through the easy part and then proceed in the lower part by swimming.  The DPVs are awesome (also called scooters).  That’s the truth.  I always wanted a scooter – but I never got one.  Fortunately, my dive buddy had just recently upgraded his DPV for a bigger one.  That meant that he still had his old one.  BOOM – scooter time,

You’ve seen these scooters.  They are basically small torpedo looking things (not exactly) with an electric motor.  You connect a line from the scooter to you so that you can “drive” with one hand.  That’s not really important, but I just wanted to say that.

Ok, so we start off on our dive.  I seem to recall that it’s sort of tricky getting into Twin Cave.  The main entrance is a vertical shaft – but then you have to turn horizontal right when you get in.  If you don’t turn correctly, you hit the the bottom of the cave.  Most cave bottoms have this silt stuff – if you hit it you change the cave water from pristine clear water to brown soup that you can’t see through.  So – don’t hit the bottom (this will be important later.  Oh, it’s even harder to get in this cave when you are trying to do with with a scooter.  We probably had a stage bottle too.

I guess I should say something about stage bottles – for completeness.  A stage bottle is an extra scuba tank that you mount on your side.  You use this stage bottle for the first part of the dive – until it gets 2/3 full.  At that point, you take the tank off and leave it on the line (there is a line running in the cave).  You then proceed on the dive using the two tanks on your back.  Using stage bottles lets you go much farther than just with double tanks.

Now back to the dive.  The first part of the cave is pretty cool.  It’s this big cylindrical cave that we called the subway.  Ok, that might not be true.  In my mind, we called it the subway.  It was super easy to get through with a scooter – just imagine a long straight circular tunnel with a diameter of about 3 to 4 meters (let’s say 10 feet for imperials).  Like I said, this is perfect for scooters.

At some point, we moved down to some small stuff and dropped off the scooters.  There are two important points here.  First, this part was deeper (can’t remember the exact depth) such that we will have more decompression time.  Second, it was low and slow down here – longer time at depth also means more deco.  I’m not going to really talk about deco time right now – but let’s just say that you don’t want to rack up a ton of deco time – it sort of sucks.

So we did our exploration of the lower part.  Now it’s time to get the hell back to the entrance and do our deco.  No more sight seeing – just hurry up.  We pick up our stage bottles and our scooters and scoot out.  Oh, quick note.  There are two things that are awesome to see in a cave.  The first is the warm glow of the Sun when you are near the cave entrance – this tells you that you are almost out.  The second is your stage bottle.  Picking up a stage just says “hey, you just got a bunch more air and a completely independent air supply – you have less chance of dying now”.  It’s awesome.

Now for the whole point of this story.  We are there on our scooters moving out of the cave while back in the subway.  Ahead we see some lights.  It was Pat and his two students.  As we start to get near, something happens.  The inflator on Pat’s buoyancy compensator (BC) just falls off for no apparent reason.  In case you have never been diving, the BC is basically a bag of air that you can fill up or empty to adjust how you float in the water.  It’s super important in cave diving because you want to stay off the bottom of the cave where all that silt is (remember I mentioned this before).

When Pat’s BC failed, so did his ability to stay off the bottom of the cave.  It was weird – he just took a dive straight down.  He sort of looked like a B-17 bomber that had just been shot out of the sky.  I saw him try to make a correction to his buoyancy, but it wasn’t going to happen.  He ended up just putting two fingers straight down to catch his fall (this is what we were taught so as to minimize the silt disturbance).  It didn’t work. His crash produced silt.  A lot of silt.

It was really amazing.  This clear water subway tunnel suddenly turned into a tunnel with a wall.  A wall of silt.  You really can’t see much in this silt – it’s effectively zero visibility (but not as bad as clay in the water).

Since we were traveling along at a good pace with the scooters – it only made sense to slow down quite a bit.  I knew there were three divers inside that wall of silt, but I didn’t know WHERE exactly they were.  So I slowed down.  Gradually clicking the throttle trigger on the scooter to maintain a slow crawl speed.

To my surprise, my dive buddy chose a different strategy – he decided to just keep going at his current speed.  I saw him head straight into that wall of silt – waiting for some type of collision.  But no, he made it though.  It was a bold move and it paid off.

For me, I went through slowly and made it to the other side of the silt wall (which wasn’t very thick).  After that we did our deco and finished the dive.  I sort of recall not taking the boat back to the van and staging area.  Instead, we used the scooters the rest of the way.  It didn’t matter at that point – you don’t have to worry about saving scooter battery or scuba air.

The end.

Astronomy and Space Posts

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Here are some posts for you.

MacGyver Season 1 Episode 2 Hacks

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Now I’m excited.  This is an episode that I fully looked at before they started working on it.  Actually, it’s sort of funny.  I remember getting this script and I remember reading it.  I was on my way to give a workshop in South Africa and I had a 9 hour lay over in Paris.  I sat in a lounge chair and read this script.

Oh wait.  I even have a picture of where I was sitting.

Ok.  That has nothing to do with MacGyver or science – it’s just one of those things that comes to my mind.  I don’t know why.  Now for some science.

Episode 102 Metal Saw

Siphoning Gas

(Plausible, fluids, pressure)

A siphon is actually pretty cool.  The basic idea is that water (and most fluids) don’t really compress that much.  If you get a fluid in a tube and the fluid moves down – it would leave an empty space after it moves.  This empty space would have a region of lower pressure.  That means the far end of the tube will have a region of higher pressure due to the atmosphere.  This higher pressure pushes the fluid.

But here’s the trick.  You can get this siphon flowing by itself – but there can be no air in the tube AND the end point must be lower than the starting point.

Gasoline Draino and Fertilizer

(Plausible, chemistry, explosive)

Ok, let me get this out of the way.  The general rule for bombs is the following: any two or three chemicals mixed together can potentially explode.  The details don’t really matter too much.

Why? Well, first – bombs are dangerous and no one wants to encourage bomb making. Second, you don’t want to train people how to make real bombs.

Ignite Alcohol with Cigar

(Plausible, fire, burning)

Really, there are two questions here.  First, can you light alcohol on fire?  The answer to this one is – yes.  Often, the idea is that alcohol over 100 proof will burn – but that’s not always true. The important thing to realize is that it’s actually the vapors that ignite – not the liquid.

Now for the second part. Can you light it with a cigar?  Probably.  You really want an open flame – not a smoldering bit of tobacco.  However, if you suck in air – you can probably get it hot enough to ignite.  It’s not a sure thing though.

Dropping a rock down a shaft

(Real, physics, acceleration)

So, a rock drops down a shaft.  By measuring the fall time, you can determine the height.  I won’t go into all the physics details – but here is a post I wrote for something else.

Arc Welder from a Car Battery 

(Plausible, electricity)

Yes, you can use car batteries to make an arc welder – but a normal car battery is only 12 volts.  It looks like you would need a few more to get up to arc welding voltage.

But wait! Can you cut instead of weld?  Yes apparently.

Using a Camera to Make Infrared Night Vision Goggles

(Real, light, vision, infrared)

How can you see in the dark?  Answer: you can’t.  Humans need visible light to reflect off objects in order to see them.  No light means no seeing.

However, you can make a type of night vision goggles using infrared.  Infrared is just like visible light – but with a slightly longer wavelength.  Human eyes can’t see it.  But wait! Some cameras can indeed see infrared – and that’s where this hack comes from.

If you take some infrared lights – lights that only produce IR then they can shine on things and humans can’t see it.  That’s where the camera comes into play.  So, it goes like this:

  • Infrared lights (like from a TV remote or a security camera).
  • Camera to pick up reflected IR.
  • Video screen so that a human can see it.

Note: there was lots of back and forth getting this thing to work in the episode – but eventually we got something good.

Oh, there is a difference between NEAR Infrared and FAR Infrared.  Near IR is stuff that is almost the same wavelength as visible light – that’s what some cameras can detect it.  FAR infrared is stuff that we associate with thermal radiation – I will talk about this later.

Now for a video.

Sunlight and Mirrors to Ignite Ammo

(plausible, light)

Yes, the sunlight gets hot.  If you can collect enough and focus it – it will get hot enough to burn stuff.

Razor Wire Caltrops

(plausible, physical)

MacGyver makes some caltrops out of wire – straight forward.

 

List of Teaching and Learning Posts

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Here is a collection of post for students and faculty – all about learning to help with the start of the semester.

List of Tweet Threads

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https://platform.twitter.com/widgets.js

https://platform.twitter.com/widgets.js

https://platform.twitter.com/widgets.js

https://platform.twitter.com/widgets.js

https://platform.twitter.com/widgets.js

https://platform.twitter.com/widgets.js

https://platform.twitter.com/widgets.js

https://platform.twitter.com/widgets.js

The Physics of Scale

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Alternative title: “Big things are not small things”.

Here are some of my posts on the physics of scale.

MacGyver Season 1 Episode 1 Hacks

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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.

(Iffy, physics, electromagnet, radio waves)

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)

I assume you can pick a lock with a paperclip.  Nothing more to say about this.

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.

Update on Python Physics Curriculum

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So here is the deal.  I had this idea.  The plan was to include numerical calculations into the intro physics curriculum by writing a sort of online textbook.  Or maybe just redo my Just Enough Physics ebook to include more numerical calculations.  Anyway, this is what I came up with. It’s written with trinket.io – an online implementation of python that pretty much rocks.

Here is my curriculum (it’s incomplete – but totally free).

Introductory Physics with Python

Here are some of my own thoughts on this curriculum (including using trinket.io):

  • It’s free and online.  That’s mostly good – but I don’t know if online is the best format for physics.
  • There is one thing about trinket.io that makes this rock.  There is python RIGHT IN THE PAGE.  Readers can view and run code – no logging in, no saving, nothing.  Just edit and run.  No barriers.
  • It has the same idea as Just Enough Physics in that it goes over the basic stuff – but doesn’t overload the student with tons of different ideas (no fluid dynamics, waves, buoyancy, sound…).  It’s not that those are bad topics, it’s just too much.  Too much.
  • Homework.  Students want homework questions.  I sort of added those in – but students seem to want traditional homework questions.

Now for the part that needs work.  Well, all of it needs work – it’s not complete.  But I made an error – I figured I would finish this curriculum as I was using it to teach the summer session of physics, but the pressure was too much.  In the end, I think I made it too much like the traditional format of a textbook (with the traditional order of topics).  Really, I started along the best path – but went off the rails when I wanted to do a problem that involved new physics.  So, I just added that new stuff in there.

I need to rethink just what I want to cover – and here is my new plan.

  • Kinematics in 1-D and 2-D. I like starting with kinematics because students can model motion and this works great with numerical calculations.  The one problem is that you have to use acceleration instead of change in momentum – and this messes up with my momentum principle.  Actually, maybe I will just do 1-D motion so that I don’t need vectors.
  • Forces. I don’t really want to focus on forces and equilibrium, but the students need this to do more stuff.  In this, I need to do the following.
    • Vectors.  Boom – need vectors.
    • Special forces: gravity, real gravity, maybe Coulomb force.
    • What about friction, and forces of constraint (like the normal force)?  Here you can see how it gets out of hand.  Friction is super crazy if you think about it – so are normal forces.
    • What if I just did simple forces – like pushing with your hand or rockets?
  • Momentum Principle.  Here I need to make a connection between forces and motion.  Since I used acceleration before, I need to make a connection between the momentum principle and \vec{F}_\text{net} = m\vec{a}.  Honestly, I hate calling this Newton’s Second Law – it seems wrong.
    • But what about circular acceleration?  How do you deal with that?  I don’t know.  Maybe just avoid it for now.
  • Work Energy Principle. I think this is mostly ok – except I need to introduce the spring force and spring potential energy.
  • Angular Momentum Principle.  My initial idea was to cover “Three Big Ideas” – momentum principle, work-energy, angular momentum principle.  However, there is SO MUCH baggage associated with angular momentum principle.  Much of this stuff is just beyond intro-level students.

I think I have a new plan.

  • Start with kinematics in 1-D.
  • Forces – but simple stuff.  No friction.  No normal forces.  All the examples will be in space or something.
  • Momentum Principle and acceleration. Again, normal stuff.  No forces of constraint.  Mostly space stuff because that will be fun.  Projectile motion stuff too.
  • Work-Energy Principle.  Springs, gravity, dropping objects.  Orbits.
  • Special cases.  Instead of Angular Momentum, I’m going to go over forces of constraint, friction, normal forces, circular acceleration.

The end.  Oh, I need to make sure there are plenty of exercises for students.  Rewrites coming.

Thinking about labs

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I need to redo all my physics labs.  They are terrible.  I want to make them even MORE about model building.

With that in mind, I saw this:

 

One sentence labs.  Leave the procedure up to the students.  I think I will need some type of turn in sheet for these labs though.  What about informal lab reports?