MacGyver Science: H2O + Orthophosphates + Mission City + Corrosion + Origins

DIY Catchpole

MacGyver is trying to find a missing phone and he gets Riley to track it down — but it’s moving. It turns out that the phone is in a storm drain moving along with the water. When he finds it, he needs to grab it out with a pole — a catch pole.

Image: CBS/MacGyver

The key idea for a catch pole is to have a tube with a string running down the middle. This string then makes a loop on the other end. When you pull the string, the loop gets smaller. For MacGyver’s version, it’s a closing bag instead of a loop.

Here is a nice video of a catch pole that you can build yourself.

But the real question: could they unlock the phone? I guess Auntie turned off the pass code. She was such a trusting person. She always was.

Perimeter Alarm

If you want to stay hidden, how do you make sure you know when someone is near? The answer is a perimeter alarm. This one probably uses a phone or some other wifi device — but the idea is simple. Make a string. When the string gets pushed or pulled, you get an alarm (or notification).

Here is a super simple alarm that you can build yourself.

This works with some type of insulator between two conductors. If the insulator is connected to a string and the string gets pulled, the two conductors touch to complete a circuit and basically become an “on switch”. In my example above, this turns on a buzzer — but it could just as easily be set to send a text message.

Bypass a Security Door With Smoke

I don’t know if you are aware of this — but there isn’t a door that can’t be breached. Oh sure, some might take a longer time — or more work, but they can all be bypassed. Really, a locked door is just a social contract that says “hey, don’t go past this”.

So, there are lots of ways to get through a locked door. In this case, there is a motion sensor on the locked side that allows humans to easily leave a building (but not enter). That means, MacGyver only needs to trick the sensor into thinking that there is a human on the other side of the door — and he does this with smoke.

In this case, he cuts off a bit of shoe string and then uses friction (with two boards) to get it to smoke. He drops the smoking string in a can and then puts the can up to the crack in the door. When he squeezes the can, the smoke goes inside and fools the sensor.

This is totally a legitimate thing.

PS: don’t break people’s social contract and go through locked doors.

Orthophosphates and Corrosion Control

Sometimes humans do things that turn out to be not such a good idea — like deep frying candy bars or using lead pipes for water supply. Oh sure, it might seem like lead is a good choice for a pipe since it’s cheap and easy to use. But it’s a terrible idea. Lead is bad for humans.

But what do you do with all the lead pipe that was already in use? No one wants to dig that stuff up and replace it. Well, one option is to use orthophosphates. When this is added to the water, it reacts with the lead surface to form a layer of “crust” so that the water no longer contacts the lead.

If you stop using the orthophosphates, the protective barrier goes away. Wait, it gets worse. If you are using water from a river then forest fires can produce chemicals that get into the river and make it more acidic. This increases the lead corrosion EVEN MORE.

This stuff is unfortunately real. It’s basically The short story is that we need to replace all of our lead pipes — the orthophosphates is just a short-term fix.

Conductivity Test

MacGyver wants to see how acidic the water is — to see if it’s part of the corrosion problem. The basic conductivity test is to apply a change in electric potential to the water (with two probes) and then measure the electric current that you get.

These are fairly simple devices. Here is a super simple one.

Another way to test is to apply a voltage and see if there is an electric current to see if you get electrolysis. This is what happens when the water is split into hydrogen and oxygen. It’s actually pretty cool and something you can do yourself.

However, MacGyver never got around to finishing his test — the bad guys interrupted him.

Water Based Shock

Once a bullet penetrates a pipe, water shoots all over the bad guy. MacGyver takes his live electrical wires and drops it in the water. Would this shock the bad guy? Well, it’s possible. You never want to mess around with live wires exactly for this reason.

There is one very important element you need for an electric shock is a complete circuit. This means that the electric current starts from one wire power cable (it has two wires in there) then somehow makes it through the human and then back to the other wire.

If the water is conductive (pure water is not), then it can be part of the path to the human. It helps that the water is spraying so that it gets his pants and shoes wet. Without that, it be tough to get past shoes with rubber bottoms (rubber is an insulator).

Canned Air Flame Thrower

OK, not an actual flame thrower — also, this is a “Bozer moment” and not a MacGyver moment. In order to get away from some bad humans, he takes a can of compressed air and a lighter. If you turn the can upside down, you don’t get air out of it — you get the propellant which is flammable.

Here is a nice MythBusters Jr. segment where they tested this out.

Physics faculty, science blogger of all things geek. Technical Consultant for CBS MacGyver and MythBusters. Former WIRED blogger.

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