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.