MacGyver Season 1 Episode 7 Science Notes: Can Opener

Let’s do it.

Ring of fire

MacGyver uses a fire hose to spray gasoline on the ground and then Jack ignites it with a bullet. It looks cool, but there are two problems. One small problem—bullets don’t make sparks (usually)—http://www.cracked.com/article_19781_6-stupid-gun-myths-everyone-believes-thanks-to-movies.html.

Oh, also gasoline doesn’t always burn that well.

OK, but gasoline CAN burn and bullets CAN make sparks—so this isn’t completely crazy.

Fixing an inhaler

MacGyver uses part of a plastic force to fix the part that pushes the release valve of a broken inhaler. This is exactly the kind of thing MacGyver would do.

Battery hydrogen bomb

OK, this is mostly real—but very awesome. Here’s how it works. If you put an electric current through some water, you can break the water into hydrogen and oxygen. In order to do this, you need the water to be able to conduct electricity. NEWS FLASH: pure water doesn’t do this. If you add some salt, water conducts just fine.

Now with the current going through the water, you get tiny bubbles. Bubbles on one electrode (I can’t remember which) are bubbles of hydrogen gas. The other set of bubbles on the other electrode are oxygen.

You can seriously do this on your own. It’s really not hard.

But how would you make an explosion? You can let the hydrogen and oxygen gas mix together—nothing will really happen until you get a spark to star the reaction between the two gases at which point BOOM.

So, in the case of MacGyver he wants to let the hydrogen gas collect at the ceiling. Yes, the hydrogen gas would rise but it’s also difficult to contain. Any tiny crack and it’s gone—but still, it’s a good idea.

What about the ignition? A spark will do. Yes, you can indeed get a spark from a fluorescent light. Especially from the ballast since it makes a high voltage.

Oh, one more comment. What about the 2 psi pressure difference? Is that possible? Probably. Would it knock the door off? I think so—especially if the pressure change is quick. Would it be bad for humans? Could be.

Morse code with the tail lights?

Totally legit.

Final breakout part 1: making liquid nitrogen

OK, this is a stretch. MacGyver uses a carbon dioxide fire extinguisher and some alcohol to make liquid nitrogen. It doesn’t say liquid nitrogen, but that’s what it is (from the air). Let me just show this video:

See. It’s possible. It’s not easy, it’s possible. What about the dry ice? Well, that’s another stretch. Expanding carbon dioxide from a compressed tank CAN INDEED make dry ice. In fact, that’s how we do it in chemistry sometimes.

Final breakout part 2: breaking steel

MacGyver takes the liquid nitrogen and puts it on some steel bars. The get super cold and breakable. The first problem: you would need a lot of liquid nitrogen to cool off the metal. But OK. The second problem—there really isn’t another problem. If you get it cold enough, I think it would work.

Adventures in Spark Gaps

I wanted to build a spark gap transmitter—you know, for fun.  However, things didn’t start off so great.  Here is how it went down.

My first plan was to build this.

I like it, but it uses an ignition coil and some other thing.  However, check out the receiver.  That’s awesome.  It’s a coherer receiver (I think) and it basically detects a spark with those two bolts in the plastic sleeve.  There should be some iron filings or something in between the bolts.  When a spark is detected, the filings jump the gap and make it a conductor.  I’m not sure why the LED light is connected to a 9 volt battery though.

After that, I just did some google searches for spark gap transmitter and attempted to build the designs I saw.  None of them had capacitor values, so I just had to guess.  But they didn’t work.

I honestly thought I knew how to do this.  I tried a step up transformer with a capacitor.  Nope.  Actually, I was getting a spark on the battery side but not the step up voltage side.  How did I even pass physics courses?

Here is my attempt with a transformer.

Finally, I found a page that used an electromechanical bell.  That works.

I decided to build my own oscillator from scratch.

Homework (for me)

  • Make this more solid (the connection to the steel plate is iffy.
  • Could you replace the steel plate with a paperclip?
  • Can you change the buzzing frequency by adding weights to the oscillating bar?
  • Use a step up transformer to get BIGGER SPARKS.
  • What about an antenna?
  • Build a coherer detector.

Fixing Stuff Isn’t So Bad

Today it started with a lose bolt that holds down the toilet.  Actually, the bolt was gone – beyond gone.  Rusted away.  I figured the flange thing that the bolts go into was probably busted too, but you can’t tell until you lift up the whole toilet.

When starting a project like this, I always go to youtube first.  What a lucky time to live in that we have a resource like this.  Of course it wasn’t just the broken bolt.  I needed to replace the wax seal too.  As long as I’m working on the toilet, I should also replace that tank fill valve that was slightly leaking.

Oh wait! When I turn off the water to the toilet with the shutoff valve, that is leaking too!  After a trip to the hardware store and multiple rounds of turning off the water to the whole house, I finished the job.  The seat doesn’t rock, the shutoff valve doesn’t leak, and the fill valve stops when fill.  Oh, how about a quick advertisement for those quarter-turn shutoff valves?  My house has these “multi-turn” valves that are like the kind on your outdoor water hose.  I’ve already had two of these leak – so that’s not so good.  Also, when the toilet overflows (it happens), the quarter turn is faster to shut off.

 

IMG_5448

Photo: Rhett Allain

I’m just going to say one other thing about toilets (this is not a toilet post).  It seems like a pretty simple job – but once you get confined in space, everything gets just a little bit more complicated.

OK, but in the end – it’s finished.  In the end, I’m pretty happy.  I feel like I accomplished something.  I fixed something and made it better.  I feel human.

I wasn’t always like this.  I remember in my early adult years I would think:

Why can’t they just make toilets that don’t break?  For that matter, why not make a lawn that doesn’t need mowing.  Oh, how about clothes that don’t need washing?  All of this cleaning an fixing stuff is just taking away time from more important stuff.

That was the old me.  The new me doesn’t mind these chose so much.  Oh, I still get bothered sometimes.  When the lawn needs mowing and it’s super hot (or won’t stop raining) or when something breaks and you JUST KEEP MESSING UP.  Yes, those times are frustrating.

But I’ve come to accept that we live in a world that increases in entropy.  If you leave stuff alone, it will just mess up and eventually break.  What makes humans so awesome is that we can fight this tide of increasing disorder.  We fix things.  We clean things.  We are humans.

 

 

Peltier Cooler

I have this small wine-refrigerator that is both old and not working.  I don’t really need it, but it’s nice to keep extra beers and wine in there.

My idea is to get a peltier cooler and convert this from a compressor cooler to a solid state cooler.  Of course it won’t be as efficient or cold – but as long as it gets just a little bit cooler I will be happy.

I ordered some coolers online (they weren’t super expensive) and they seem to work. It requires 12 volts and up to 5 or 6 amps – so the power supply might be an issue (it seems many people use a computer ATX power supply).  Actually, you can just connect it to a D-cell battery and put your fingers on each side of the cooler and easily feel a temperature difference (great for demos).

With a temporary power supply, I put the cold side of the peltier on a big aluminum block and then I put a cpu heat sink on the hot side.  This didn’t work – but here is a picture.

IMG_4732.jpg

It turns out that the peltier cooler gets hot – but it keeps a temperature difference between the two sides.  So the key is to keep the hot side as cool as possible.  With this in mind, I switched it so that the hot side was on the block and there was nothing on the cool side.  I still didn’t work very well until I put some thermal paste between the peltier and the aluminum block for good thermal contact.

Here is what I get.

Pretty cool, right?

I will keep you updated.