In order to escape from a dinner, MacGyver opens all the gas outlets in the kitchen to fill the building with gas. He then takes apart a pay phone and disconnects the ringer. Super old pay phones (what’s a pay phone?) have a mechanical oscillator that rings a bell.
In order to get some heavy pieces on top of a house (to rebuild the roof), MacGyver uses a rope running over a movable ladder to act as a type of crane. I thought I had a pre-show sketch of this, but I couldn’t find it.
Fixing a flat tire
The truck has a flat tire. MacGyver needs to do two things—plug the hole and fill the tire. To plug the hole, he uses a bit of rubber and heats it up. Then you just push this through the hole in the tire. That’s it. Honestly, I have done this with an actual flat tire and I was surprised that it worked.
For the air, MacGyver connects the tire of the scooter to the truck. Yes, this would add some air to the truck tire from the scooter tire—but only until the two tires reach the same pressure. That might plausibly be enough air to get you going, but likely not.
If you want to get more air from the scooter tire, you could heat it up. When the air in the scooter tire increases in temperature, it increases in pressure. You need the scooter tire pressure higher than the truck tire to get a transfer.
A basic radio really isn’t all that complicated. You need a capacitor, a coil of wire (for the inductor) and some type of diode. Soldiers used to make them from scratch on the front line in WWII—they were called foxhole radios.
Ok, but what if you want a two way radio? Yup, it’s much more difficult to transmit. But still, you get the idea. Here is a sketch from the show notes.
Dye pack explosion
So these banks have these exploding packs of dye. That way they can toss them in with some money when bad guys steal stuff. Some of the packs are radio activated, but others go off (after a delay) when passing out of the main bank area. https://en.wikipedia.org/wiki/Dye_pack
MacGyver just puts one in a coffee cup and tosses it past the door. Since it makes a noise, the baddie goes to investigate and BOOM. Ink in the face.
Ethernet rope ladder
MacGyver makes a rope ladder out of ethernet cable so that people can escape from a second story window. It might take a while to make, but this is fairly legit.
I honestly can’t remember the exact kind of bomb MacGyver is making here—and that’s fine because I wouldn’t tell you anyway. But he uses some stuff from the bank to get into the sewers below.
Falling telephone pole
For the last hack, MacGyver hits a telephone pole that’s ready to fall over anyway. The pole falls and lands on the bad guys car. The end.
It’s the beginning of a new school year—and I’ve got you covered. You want to do something with coding in your physics class, but you don’t know where to start? I’m going to give you a jump start.
I know you are nervous, but don’t worry. You don’t need to be a ‘l33t h4x0rz’ (that’s cool-speak for elite hacker). You just need to get started. Just remember, everyone had to start programing at some point. They all did it—so can you.
What the heck do you call it?
I like to call this stuff “numerical calculations”. I think this is the best name for it because it sort of describes what’s going on. Here’s the general idea:
Take a physics problem (or any problem, really).
Break the problem into a bunch of small and easier problems.
Maybe make some approximations.
Solve all the small problems by using numbers.
Numbers are the key. You have to use numbers in a numerical calculation. The other solution is an analytical calculation. This is the process of solving a problem in terms of known functions—like the trig functions. For an analytic solution, you don’t really have to put in the numbers until the end.
Of course, there isn’t a huge difference in these two solutions (analytical vs. numerical). A great example from Bruce Sherwood (in a discussion at the recent AAPT meeting in Utah) points out the following:
Suppose you get a solution for a mass oscillating on a spring. The analytical solution will be in terms of the cosine function. But then, how do you get values for something like ? Well, you put it in your calculator or you look it up in a table. Oh, you could find the value for cosine by summing an infinite series. But you see—we are back to a numerical calculation.
That’s not exactly what Bruce said, but that’s the basic idea.
Here are some other names for numerical calculations that you might see:
Coding in physics
I’m drawing a blank here—there must be some other words.
But I also like numerical calculations because it doesn’t explicitly say “computer” in it.
Why do numerical calculations in physics?
Let me be brief and just list some points.
Numerical calculations are just part of physics. There are countless physics problems that can only be solved numerically.
Once students get the idea of numerical calculations, they can solve more interesting problems that would otherwise be inaccessible to them.
What about other fields? Meteorology, digital animations, protein folding, economics…the list goes on.
Tools. The tools for numerical calculations are both free and easy to access. You don’t need to install anything and you could even do it on a smart phone (not recommend—but possible).
Finally, numerical calculations helps student understand physics. I’ve always been surprised that when working on a problem with students on a computer, they ask questions. But these questions are rarely about computer syntax. They are usually things about vectors or forces. It’s awesome.
Who is this for?
I’m going to get you started—so this tutorial is geared towards very introductory classes. I use this same stuff in a physics lab for an algebra-based physics course at that college level. I think this would be fine for high school classes also.
If you want more advanced stuff—this might also work as an introduction. For my calculus-based physics course, I start with more complicated stuff.
Also, I am careful to emphasize that students (and faculty) don’t need any prior experience with coding.
Where to start
I like to have a workshop format for my lab or class. I use a projector at the front of the room to go over some points and then stop and let the students work on code either individually or in groups (here is a version of my presentation—feel free to use it). I tell students to bring a computer or tablet if possible. Otherwise they will be in groups of 4 per computer (which is not ideal). Of course some students don’t want to get involved, so a 4 person group is what they want.
Here is the general outline of the workshop format lesson.
Give an overview of numerical calculations (motivation).
Start with an object moving at a constant velocity in one dimension. Let them solve it analytically (hopefully, this is a review).
Next have them take this SAME PROBLEM but solve it by breaking into 7 time steps—but still solving it on paper. NO COMPUTERS YET.
I actually give them a table to fill out. It has 7 rows with columns for time, time step, and position. After a short time, I stop them and go over the calculation for the first row (and maybe the second). Some students can finish this table very quickly, and others not so quick.
Next, they do this same set of calculations with some python code. I give them this program that runs as it is and I go over each line.
So, the students run the code and then modify the code to answer some questions such as:
Where will the car be at a different time? Say 2.2 seconds.
What if you change the velocity the 0.62 m/s, where will it be after 2.2 seconds?
What if the car starts at -0.5 meters?
Stuff like that. Really, I just want them to be able to run the code, read the output, and change the code. It’s sort of a coding ice-breaker.
I’m not going to go over the rest of the workshop—but it’s all there (and more) on the trinket.io site along with the instructor slides. After that first small activity, the students do the following:
A similar problem but with a constant (non-zero) acceleration. This is great because you get a different final answer for the numerical calculation that depends on the size of the time step.
How to make graphs (or at least print out values) so you can get more data.
Solving a problem with two cars—one moving at a constant velocity and one accelerating. This is the classic “police chase” problem. I set up the program (not all the way) but I let them figure out how to change the while loop to get it to run. It’s great because students come up with their own ways of making it work. Sometimes, this is where I stop the class.
Mass oscillating on a spring.
What do you need?
If you want to do this in class, you need some computers or tablets and some time. You could probably do this in sections, just break it into 30 minute activities if you like.
Some other things to consider:
Make sure you work through the material first. It’s important to really know what’s going on so that you can easily help students when they get stuck.
If a group has a program that’s not running right, I really try to get them unstuck. If it’s a silly syntax error, I try to find that right away so they don’t get frustrated.
If you have any questions or need help. let me know.
Hand sanitizer is mostly ethyl alcohol—it burns fairly nicely. Oh, but don’t play with fire. If you put this stuff on a roll of paper towels, it should make a great torch. It would probably have more of a blue color though.
Actually, you can just squirt some hand sanitizer on a cement floor and light it on fire.
This is a “Riley hack”. Since the power is out in the building, she hacks into the wifi routers for the nearby buildings. By looking at the strength of the wifi signals that go through the building, she can sort of judge where people are moving.
Oh, this is crazy? No, this is based on some real stuff.
That glow stick that you use for Halloween is just a mixture of two chemicals. In that particular chemical reaction, it is an example of chemiluminescent—a chemical reaction that produces light. It’s sort of cool.
It’s not perfect, but it is possible to make your own glowstick.
You can’t really see exactly what MacGyver has rigged up—but it’s a type of descender. The basic idea is that when a torque is applied to a ring around a line, it binds up with a frictional force to prevent it from sliding.
Here is a diagram I created that might help explain how this would work.
These two loops around the elevator cable could be just about anything. One idea was to use some padlocks—but as long as it’s stiff and goes around the cable, that’s fine.
So, here’s how it works.
If MacGyver puts his weight on the bottom element, it will provide a torque and bind up against the cable.
He can then move the top element down.
Next, he hang from the top element so it binds and then he can move the bottom thing.
DIY Tesla coil
A Tesla coil is essentially a device to create a very large electric potential difference (many would say high voltage). The most common method is to use a series of transformers—a way to convert AC signals to higher voltage (yes, I said it).
For MacGyver’s hack, he uses the ballast from a bunch of fluorescent lights. A fluorescent light starts with a tube of gas. Electrons are accelerated in this tube and interact with the gas molecules to produce light. This light is in the ultraviolet range, so you really can’t see it. But there is a coating on the inside of the tube that absorbs the UV and produces white light—this is the “fluorescence” part of a fluorescent light.
But the key is high voltage. Yes, the electrons need to be accelerated over an electric potential difference that is greater than the usual 120 volts from your AC outlet. That’s where the ballast comes into play. This takes the 120 volts from your household circuit and ramps it up to something like 500 volts.
What about a Tesla coil? If you want to get cool (and giant) sparks, you will need about 5,000-30,000 volts. So, would 10 ballasts do the trick? Probably not—the voltages just don’t add up that way. But still, it’s based on a real thing.
You can’t “block” electric fields that are associated with things like sparks and electromagnetic waves—but you can make more electric fields that produce a zero electric field. That’s what a Faraday cage does. It creates more electric fields that cancel an external electric field.
Here is a very basic example. Suppose I have a constant electric field and I want to “block” this. If I put a piece of metal around me, the external electric field will move charges in the metal and these charges will create more electric fields. When you add all the fields up, you get a zero field—it’s just like the field is canceled.
The cool part about a Faraday cage is that it doesn’t even have to be solid metal. You can still have holes in it and it will cancel electric fields. Here is an example of a Faraday cage with a radio and some aluminum foil.
This is just the beginning of the show, so we don’t really know what’s going on except that Riley, Jack and MacGyver are on a trampoline supported by a bunch of balloons.
So, I will just leave this as a homework question for you. How many balloons would you need to lift 3 humans?
Pinned down by gunfire, MacGyver needs a way to distract the baddies so that they can make their move. Angus takes his phone and plugs into an audio sound system and plays some high pitched song. This is the classic demo of singing to break some glass. Of course, that doesn’t usually involve a glass window—but still this is all about resonance.
If you go out to a playground, you can find a nice swing. If you push the swing at regular intervals, you can get the swing amplitude to increase. But here is the key point. The frequency of the pushes has to be the same as the natural oscillation frequency of the swing. Otherwise, your push might be timed at the bottom of the swinging motion which could cause the thing to slow down.
If you want to break glass with sound, it is indeed possible. Here’s what you do. Take some glass and give it a nice little tap so that it makes a ringing tone. Measure the frequency of this ring and then play that same frequency with a speaker—it’s got to be LOUD for it to work.
Of course loud noises and breaking glasses aren’t always safe. Here is an alternative demonstration with resonance. As a bonus, you can use this as a magic trick for your friends.
Detecting counterfeit money
They have all these 100 dollar bills. The suspicion is that they are fake—they are one dollar bills reprinted to be 100s. MacGyver puts them in an acid solution to dissolve the new ink as a test.
GPS phone tracker
MacGyver takes the gps receiver along with a battery from a phone and creates a tracking device. Of course the gps is actually built into the processor for most phones—so let’s just say he takes that whole thing (along with the LTE transmitter). Yeah, this would basically work.
Duffle bag battering ram
There is a duffle bag filled with cash. MacGyver hangs this up and uses it as a type of battering ram—to knock over a bad guy.
When MacGyver brings in the counterfeit money, he says:
“Yeah, well one million dollars in 100 dollar bills is actually only 20 pounds…so…”
Through an odd sequence of events—actually, not odd but academically sad, I am going to be teaching the intro astronomy course this semester. OK, if you MUST know the reason, here it goes.
You know I love teaching this Physics for Elementary Education majors course, right? Yes—it uses the Next Gen PET curriculum (which is AWESOME). I put this course together sometime around 2005 for the College of Education. They needed a hands on science course to satisfy their accreditation requirements and this course fit that need. It worked PERFECTLY.
Flash forward to today. Apparently the College of Education decided to drop this course from their curriculum without even telling us. Oh, am I bitter—maybe a little. But since the course isn’t required, I only had 2 students registered. The class was canceled and I picked up an astronomy course. The end.
Now for the astronomy class. This is a class for non-science majors, so essentially no math. I have taught it before, but that was maybe 10 years ago. I want it to be a great course, but I don’t have a lot of time to find some resources. That means I ask twitter for help.
There’s really not too much to explain here. MacGyver rolls a guy up in a carpet and uses that to keep him in place. Seems like this should work.
Reminder—even though there’s not any great science to talk about here, I love these kinds of hacks.
Pick a lock with an antenna
MacGyver pulls a metal antenna off a motorcycle and then uses it to pick the lock on the same motorcycle. Oh, this is a police motorcycle—he uses it to turn on the siren.
Is this possible? Possible, yes. Normally you need two things to pick a lock—something to move the lock pins and something to provide torque. Theoretically, you could do it with one—but it would be tough.
Radiator fire extinguisher
There’s a car on fire and they need to get something out of it. MacGyver improvises a DIY fire extinguisher by using the cooling system of another car. He grabs a pipe and then pokes a hole in the radiator. When the engine is revved up, the coolant shoots out through the pipe and onto the burning car.
Again, the theory here is solid. You could probably even get the coolant to shoot fairly far. However, it would take a significant amount of coolant to put out a fire.
Statue battering ram
This one is good. MacGyver and Jack take a marble statue and support it from some rope and stuff such that it can swing. Then they swing this statue into a door. Boom—battering ram.
Hacking airplane wifi
OK, not hacking to get free wifi but using the wifi to control the whole plane. That’s what Riley does as she is stuck on a plane with a virus. Is this even possible?
This is not a MacGyver-hack. But he is talking about radioactive stuff. Here is my super short explanation.
An atom is made of a positive nucleus plus some electrons. Normally, there will be the same number of electrons as protons in the nucleus. This makes the overall charge of the atom zero. But wait! There are also neutrons in the nucleus. Let’s just look at an example.
Strontium-90 is an atom with 38 protons and 38 electrons. It also has 52 neutrons in the nucleus—oh, and it’s radioactive. Strontium-88 also has 38 protons and electrons, but it only has 50 neutrons. Since these two atoms have the same number of protons, but different neutrons—they are isotopes of each other.
Sr-90 is radioactive. That means its nucleus is unstable. It goes through radioactive decay and produces Yttiruim-90 which has 39 protons. So, one of the neutrons in Sr-90 turns into a proton and also produces an electron (so that charge is conserved).
The half-life of Sr-90 is 28.8 years. Since the decay process is random, there are more decays when you have more atoms. This means that the decay rate depends on the number of atoms. So, you can’t say how long it will take for all the material to go through radioactive decay. Instead, we say how long it will take for half of it to decay—that is the half life.
So, does that mean that all of the material will decay in 2 times 28.8 years? Nope. It means that after 28.8 years, you will have half as much stuff. After another 28.8 years you will again have half of what you started with. Every 28.8 years, you will have half as much.
What about Plutonium? There are several different isotopes. Plutonium-238 has a half-life of 87.7 years. Plutonium-239 has a half life of 24,000 years. The shorter the half-life, the more “radioactive” it is. But for longer half-life stuff, it’s still going to stick around for a long time.
DIY Geiger Counter
A Geiger counter is a device to measure radioactivity. It consists of an outer conducting tube with a conducting wire running down the middle. The wire and tube are at different electric potentials—usually a fairly high voltage.
When a charged particle (the result of a radioactive decay) enters the tube, it interacts with the gas molecules to ionize them—knock out an electron. This free electron then accelerates in the high potential and collides with other gas molecules to produce even more free charges. More and more charges are produced—it’s called an electron avalanche. This avalanche is then detected as an electron current—usually to produce an audible click. That’s the clicking sound you hear.
Here is MacGyver’s build.
He uses a motorcycle muffler as the tube—you can’t see the wire in the middle, but it’s there. The battery provides the voltage and then there is an audio speaker to convert the electron avalanche into sound.
Oh, I forgot—here is a video demo.
Bonus. Here is my sketch for the DIY Geiger counter.
DIY Ice Climbing Gear
There’s really not much to explain here. MacGyver uses some cut up chain link fence and some rebar to make spike-shoes and a type of ice pick. He uses these to climb up an old brick wall—sticking the metal into the old mortar. It seems like it would work.
MacGyver builds one of those rolling things that mechanics use to get under cars (I forget the name). With that, he disables the trucks (all but one). Really, once he is under the truck he could do a number of things. He could cut the fuel line or cut an electrical line—let’s just say he does it.
In order to convince the mob that the key guy they are trying to catch isn’t worth it. They make it look like he is super radioactive. The mob guys have a Geiger counter—so MacGyver needs to remotely set that off.
The electron gun would shoot electrons into the Geiger counter and set off an electron avalanche in the same way that a radioactive source would. Unfortunately, it was too complicated of a build.
What about a super high amplitude electromagnetic wave? The idea is that when the electric field part of the wave hits the detector, it will increase the field inside and make it more sensitive to ionizing radiation. This would make it seem like something is more radioactive than it is. Yes, I know this is a stretch—but it’s based on some real idea.
Here’s how he could build it.
Start with a radio – it has to be a transmitting radio. Maybe a CB, maybe a portable radio?
Boost the power to the radio. I think plausibly connect the power source from the radio to the 12 volt car battery?
Get a bent piece of metal to put around the radio antenna to make a focusing dish. Alternatively, you could find some pre-existing dish- aim the dish-radio at the Geiger counters. boom.
Sorry for the delay in science notes. There were things that got in the way.
Block and Tackle
I don’t really like calling it that. A better term is a compound pulley. But the key to all of the simple machines is force vs. distance. If you increase the distance over which you apply a force, you can get a larger force output of the machine over a shorter distance. That’s exactly what happens with a “block and tackle”.
But basically it’s alcohol oxidase with some other stuff added. When mixed with alcohol, this makes aceteldehyde—the main thing that causes hangovers. MacGyver could get alcohol oxidase from alcohol test kits.
Note: I’m not a biochemist, I got this info from my brother (a biochemist).
Don’t make this stuff. But it is possible. Actually, I’m not even going to include the link.
Using a hammock as both a ladder and a body sling? Yup, that’s good. Using a chain as a DIY car boot. That works too. Not much to explain, but I think both of those hacks are great.
In order to knock out everyone in the room (including himself), MacGyver throws some chloroform in a container into a fire. It explodes and everyone gets knocked out. Sure, this would be tough to do in real life—but it’s a least plausible.
DIY Arc Lamp
Wait. There wasn’t an arc lamp in this episode was there? Nope. It get cut out of the beginning. However, I made an arc lamp anyway as part of my DIY videos. It’s awesome.
Here are some things I need to share regarding this meeting. Overall, it was great to see everyone. As usual, the conversations were the best. I regret that there were some people I did not get to meet or talk to—maybe next time we will meet up.
Blog vs. WIRED
One question that came up multiple times was about this blog vs. my posts at WIRED. How do I decide where a post goes? OK, here is my explanation.
In the beginning, there was a blog. A blog was super informal and free form and alive with comments. It was like the 60s and I was a hippie. A physics hippie. I don’t know if this early blogging era was like the 60’s or maybe the wild-wild west. Well, the comments eventually turned into the wild west with a shoot out at the O.K. Corral.
When I moved to WIRED, everything was the same except it was at a different site. But I’ve been there for a LONG time (9 years?) and things evolve. My posts at WIRED are more edited and geared for a specific audience. That’s not bad, it’s just different. I don’t think I can just write whatever I want like I did in the old days. No more random posts that just talk about my cat (I don’t even have a cat).
So, that’s where this blog comes in. It’s a place where I can post whatever I want and no one can stop me. These are the kinds of things you will find here.
Random posts (like this one) that are just an outlet for me to write stuff and tell stories.
Explicit educational material. If a post needs too many equations, I would rather put it here. Many WIRED readers (while very education) don’t really get into all the equations. Also, since WIRED is paywalled it makes it more difficult for educators to access the stuff (in the off chance that they might find it useful).
MacGyver science notes. Oh sure, I post some MacGyver stuff on WIRED—but I really don’t think they want to see 50 posts on different episodes. So, those are here.
I think that pretty much covers it, so I don’t even need this last point.
In the end, I apologize for the confusion with the two blogs. Oh, actually there are three. I recently wrote a post on OneZero Medium (analysis of a car crash from Stranger Things) also. Not sure how much I will write there—but it’s still me.
What’s up with all the drone videos?
Yes, I have a drone. I love my drone. I can only hope my drone loves me as much as I love it. Honestly, I am honored that you even noticed my drone videos.
Oh, wait. You haven’t seen them? I can fix that.
In case you are curious. This is a DJI Spark. Great drone.
Here are some more short comments.
Meeting with Bruce Sherwood and Ruth Chabay was great. I wish I had a picture with both of them (I did get one with Bruce though).
Bruce made this epic comment in regards to numerical vs. analytical calculations. People claim that analytical solutions are better because you can solve a problem in terms of known functions like sine and cosine. But how do you find the value of the cosine function? YUP – numerically or in a table or in an infinite series. So, in a way all solutions are numerical. Win for numerical.
The other deep thought by Bruce was a discussion on his AJP on energy. Read that paper. This sums it up. You can not find the work done by friction. Friction is crazy hard. I think I might write a WIRED post on this.
Eric Ayars had an excellent presentation on chaotic systems. One system was a bouncing ball on a moving floor. I wonder if there is a case where the ball just stops—this could happen if the relative collision speed of the ball and floor is zero.
The 30 demos in 60 minutes was pretty good. I love these things. Even though I’ve seen many of these demos before, I always find something new. Here is their site http://30demosin60minutes.com/
I went hiking. It was super hot, but I had a great time.