# MacGyver Season 3 Episode 13 Science Notes: Wilderness + Training + Survival

There is no funny intro for this post. Oh wait, this is an intro.

Rock and steel to make a spark.

OK, this isn’t actually a MacGyver hack in this episode but I’ve talked about it before. Here is a video.

Other fire stuff

Are there certain plants that ignite more readily than others? Yes. Here is a nice article from Field and Stream that goes over the basics.

Again, not a hack—but cotton is terrible when wet (so is denim jeans). When wet stuff is next to your body, the water evaporates. In this process the liquid water turns into a gas water (water vapor). The phase transition requires energy. Guess where the energy comes from? Yup, it comes from the human. This makes the human colder. Here is my more detailed explanation.

What about wool and other materials? The key to these better fabrics is that they “wick”—they pull the water away from the body. Here is a nice post on that.

Zipper for ice traction

MacGyver takes the tent zippers and uses them on people’s shoes for added traction on ice. It’s sort of like mini-spikes on your shoes. Classic.

How to make drinkable water

MacGyver uses a tree branch to act as a water filter. This seems to be real (from MIT) so you know it’s got to be good.

Here is a nice video showing how this would work.

Making rope (string)

I’ll admit it—I’ve never really understood how this works. If you take some vine or some other material, it has a certain maximum strength in its tension before it breaks. If you take two of these things together, it doubles the strength. If you take these two things and then twist them—the strength is more than double. What? But it does indeed work (I need to do an experiment sometime to really understand this).

Here is an older video in which I attempted to make rope from a TV guide.

Size and weight of 18 million dollars

This is a classic MacGyver estimation problem. How do you find the size and weight of a bunch of money? Why does it even matter? Well, one big thing is to find the density of the money. If the density is less than the density of water, then the crate of money would float and then be swept away in a flash flood.

Yes, you don’t need the weight and size—but just the density. However, if you want to estimate how long the crate was floating you DO need the size. Bigger crates will “hit the bottom” before smaller crates.

If you want to look at more stuff about the density of money, here is an older post in which I find out how far 1 trillion dollars would stack. Would it make it to the moon?

Surveying tools

How do you find the slope of the ground? This is where you need surveying tools. Here’s how it works. Get a scope (from a rifle) and make sure it’s aimed level. There are plenty of ways to level a scope—those little bubble levels work great. Next get a survey stick. Make sure this is also vertical and then measure where the scope points at the stick.

If you know the change in elevation and the distance between the stick and the scope you have the slope.

Float distance calculation

Yeah, this is pretty tough—but that should never stop anyone from trying. How do you estimate the distance a crate will float in a flood? Here are some things to consider (some of these would be tough to estimate).

• How fast was the water flowing?
• How deep did the water get?
• How long did the flood last?

Really, if you know those things you can calculate the speed and time of the floating crate. This would then give you the distance. From that you can find the location on a map.

Drag sled

To move a crate (or an injured MacGyver), it shouldn’t be too hard to make a drag thing—called a travios.

Grab hot coals

Don’t try this at home, but it is indeed possible to grab hot coals. Essentially, you can grab hot stuff if you are really quick. There isn’t enough time to transfer energy to cause a major burn.

It’s just like walking on hot coals. Here is a nice physics post on that.

## 4 thoughts on “MacGyver Season 3 Episode 13 Science Notes: Wilderness + Training + Survival”

1. Matthew says:

Hello Mr Allain my name is Matthew and I might have some questions about the equation that Mac does when he is finding the slope and where the 18 million dollars floated. I love MacGyver and I always want to try and do the things he does and I’m not really good with math (well his math because I’m only a freshman in HS) but I wanted to see how exactly he estimated it and what all of the letters stand for like VFlood=X/RT. Thanks and I love your work. And as always go MacGyver!!!!👌👌

1. rhettallain says:

The v-flood is the velocity of the flood waters. Honestly, there was some very rough estimations here. It’s not all shown on camera, but MacGyver used the erosion of dirt to find the approximate water speed.

X is the distance the box travels – that is what he wants to solve for (oh, this is just your basic definition of velocity = (change in distance)/(change in time) formula

the t is the time. He gets this also estimation of the time the flood carries the box by looking at the erosion of the dirt along with an estimation of how deep the box gets when floating (which depends on the density of the box-money thingy).

Hope that helps.

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