The problem with a sinkhole is that the sides of the hole are unstable. You can’t just climb up the side or lower a rope down the side. This would just cause further collapse.
The answer is to get a crane. Something that sticks out over the edge of the hole, but doesn’t interact with the hole. Really, this is mostly just a nice build—but there is one physics thing to discuss.
You can’t just get a pole and stick it out from the truck and expect that pole to lift any weight of significance. It will bend or break. You need some type of structure to allow the crane to exert a torque on the end.
Here are two ways you could do that. First, you could make a type of truss. It might look something like this:
The triangle structure in the truss makes the whole thing rigid. Also, it allows multiple forces on the support end. There needs to be a force that will exert a torque to counteract the torque from the load.
The second method is to use a cable. I’m sure there is a technical term for this, but I’m just going to call it a cable. It would look like this.
I just realized that there was a mistake on the forces for the truss diagram. But you still get the idea.
Bonus, here is my initial diagram for this situation.
What about the tire and rope thing? Yes, this should work. MacGyver takes the rope and wraps it around the tire. This means that the truck’s engine can be the power to lift the humans out of the hole.
MacGyver needs to fashion a vascular clamp from some normal clamps. To do this, he builds a mini furnace. This is real. Actually, I built one of these with my daughter so that we could melt aluminum. Here is the video we started with. Note: this is awesome, but also dangerous.
This actually works. There is something amazing about melting metal with charcoal. We started off with a charcoal furnace and an old vacuum cleaner to blow in air. It works, but it goes through a bunch of charcoal really quickly. So, we switched to a propane version—this is much easier.
Bonus—here is my furnace diagram for the show.
I don’t want to write about the flash bangs—but I should say there is a legitimate basis for this. I just don’t want to tell you.
OK, it’s not really a hammer. It’s more like a pressure gun. MacGyver hooks up a pressured line from a water heater to a tube with a rod in it. When the pressure is released, it shoots the rod and hits the door handle to knock it out. That’s great.
If you want it to “hammer” back and forth, you need to do something different. Here is a very basic design.
There is still a tube with a rod, but there are two differences. First, there is a hole on the side of the tube. As the rod moves forward (due to the pressure from the hose), it eventually gets to the part where the side hole is exposed. This would allow the pressure to escape and the rod would stop moving forward.
The other feature is a spring. One side of the spring is mounted to the outside tube and the other to the inside rod (yes, there needs to be a small slit in the tube). This spring will pull the rod back into place once the pressure escapes.
I really don’t know if this would work.
Finding Location with Sound.
This one was tough—but fun. How can MacGyver use evidence he collects to go back and figure out his location? In this case, he uses sound.
In air, sound travels at a finite speed. Technically, the speed of sound depends on the temperature of the air—but using a value of 340 meters per second is a reasonable value.
Since this sound speed is finite, it takes some finite amount of time for this sound to travel over a distance. But of course you already know this because you have seen lightning and heard the thunder. The light part of this lightning strike travels at the speed of light (which is really, really fast). However, the sound part of the strike travels much slower. This means that you see the lightning and then hear the thunder later. The farther away you are from the lightning strike, the bigger the time difference between these two signals.
For MacGyver’s case, he is going to use two sounds that start from different distances and at different times, but reach him (he hears them) at the same time. In this case the sounds are from church bells and a fire station. It’s sort of like the opposite of the lightning problem except that it’s totally different.
So, here is what he knows.
Church bells every half hour.
Fire station alarm went off at 1:29 and 58 seconds.
That means the sound from the church bells traveled for 2 more seconds than the fire station sound. How far away is MacGyver from the 2 sources? Yes, this is a more difficult problem—but it’s not impossible.
This is what MacGyver writes on the board to solve this.
Now for fun, here is my original solution.
Isn’t that fun? Well, it is for me. Oh, what about the two points? You can think of this problem as two expanding circles. Each circle represents a sound and the circle’s radius increases at a rate equal to the speed of sound. So, one circle is going to be bigger than the other one (because that sound was created first). We are looking for the places where the two circles intersect. Yes, there are two of these locations. MacGyver picks the location based on the direction of water flow in the sewer.
You know, I really should make a python animation for this problem. Maybe I will do that soon. Oh, one final note. For my solution above, I recreated the calculation so that it would have the correct values. At the time, I was at my son’s soccer practice. So this is a picture of my notes as they are sitting on the seat of the car. True.
It’s real. The basic idea is to use x-rays on the film. These x-rays excite some of the atoms in the film such that they fluoresce and produce infrared light. You can’t see the IR light, but a video camera can.
It’s something like this—a technique that is used to look at different layers in paintings.
There’s really only two MacGyver hacks in this episode—but wait! Don’t be upset, it’s a good thing. First, it happens to be a great episode. Second, when you don’t have a set number of hacks in an episode it just feels like the story uses these hacks rather than revolve around them.
I guess you can call it whatever you want. But how does it work? There are a few important things to go over. First—how do we see things? Suppose there is a pencil on a table. If you see that pencil, it’s because light reflects off that pencil and then enters your eyes. Here is a diagram (from my post on 5 Things Every Human Should Know About Light).
Second—how does a window work? In the most basic form, a window could just be a piece of glass. When light hits glass, two things happen. Some of the light is transmitted and some of the light is reflected. Yes, this pretty much always happens. OK, I lied. There are some cases where all the light is transmitted and other cases where all is reflected.
I can prove this to you. If you are inside a house on a sunny day, you can see outside but other people can’t see in. The problem is that the outside stuff is so bright that the reflected light is way more than the light coming through (from the inside) and you can’t see it. Here is a diagram (from this old post of mine).
Now back to the “one way mirror”. The key is to have the room with the observers darker than the room with the people you want to watch.
Skateboard with a pulley.
There is a door, but it’s trapped. It’s a trapped-door. Get it? OK, so MacGyver needs to bust this down but without people nearby in case it explodes (it does explode). He takes the battering ram weight and puts it on a skateboard. Then he run some string over a couple of pulleys so that he can get this thing up to speed and smash into the door.
Here is a diagram (from my show notes) to see how you would set this up.
The key to a pulley system is to set it up so that the distance the object moves is different than the distance the person pulls. In fact, this is the key idea to all simple machines (a compound pulley is indeed a simple machine).
In the diagram above, if Mac pulls the bottom pulley (this is a top view) one meter, then there would need to be two meters of string move that way (since the string is doubled over). That means the skate-board and battering ram would move 2 meters for this 1 meter of pull.
Yes, the skate board would move twice as fast as MacGyver. But you don’t get something for nothing. Although he only moves 1 meter for the 2 of the board, there would be twice the force on MacGyver. This is how simple machines work.
Slowing down a car with a winch.
MacGyver grabs the winch on the truck and then jumps to the truck with Murdoc. He wraps the cable around a post and then Oversight slams on the brakes. Both cars stop.
Yes, the friction from the rear truck would indeed slow down the other car (if not stop it). However, since the cable is attached to the side of Murdoc’s truck, the force from the cable will also turn that truck. Once it get’s turn too much, it can’t even drive straight. Now both trucks are essentially sliding with rubber wheel interacting with the road. That’s why it stops.
Is there a better MacGyver image than his radio build at the beginning of the episode? I think not. Here is an image.
Could you actually build a radio from a snow mobile? I think yes. Really, radios aren’t actually that complicated. The only difficult part would be building an amplifier so that the signal generated from a voice is powerful enough to be detected by someone’s radio. If the snow mobile had any kind of radio (like for listening), you would have all the parts you would need.
Stun gun on slot machine
They call these hand held zap things stun guns, but they don’t shoot. You just have to hold them up to someone to shock them.
MacGyver needs a distraction so he takes the stun gun and uses it on a slot machine. After that, the guy playing wins.
Is this even possible? Possible, yes. Likely, no. The stun gun has high voltage that creates sparks. These sparks can damage electronic equipment—especially the super tiny transistors in a computer chip. So, it’s possible that the stun gun does something to cause a win.
However, these slot machines are built with tampering in mind. They need to be able to resist humans messing around with them to win. So, I doubt this would work. Also, if MacGyver zaps that outside of the machine it’s probably grounded. This means that the electric current that gets into the case of the slot machine will just go around all the electrical components.
You probably have a better chance of winning on the slot machine than cheating on it.
Iris scanner hack
In order to get through an iris scanner on a door, Jack gets a close up picture of the target’s eye. Then Bozer prints out a fake lens to wear over the eye. Could this work? It’s possible.
Of course the details are complicated (which means I don’t really understand them), but you would need some type of antenna. Jack has a tiny antenna in his cuff that has to get close enough to the target’s phone. I think this is plausible. At least it would give Riley a chance to get into the phone and steal some codes.
Also known as a compass. MacGyver is trying to find a magnetic switch for a hidden door. He grabs a bit of metal (hopefully it’s ferromagnetic steel) along with a magnetic bottle opener.
The basic idea is that a metal like steel (most steel) has magnetic domains. When these domains are lined up, the material will act like a magnet. You can line up the domains by rubbing the steel with a magnet. Like this.
If the magnetized steel can float, it will rotate and point in the direction of an external magnetic field—either from the Earth or from that magnetic door switch.
OK, one small issue. In the episode it shows MacGyver rubbing the steel back and forth. You really just want to rub it one way. I think it would still work though. Oh, also many of those magnets like the one on the bottle opener have weird domains. They aren’t just like a plain north and south of a bar magnet, but it still might work.
Vacuum Cleaner Spider-Man
This is awesome (and mostly real).
Here’s how it works. The vacuum cleaner works by pulling air out of a region. If you put a vacuum cleaner over carpet, the air flow goes from the carpet to the vacuum cleaner (basically with just a super powerful fan). When the air moves in this manner, it often picks up other stuff—like dirt.
MacGyver has this vacuum hooked up to some metal tray covers. When the air is pulled from these covers, the air pressure inside the covers decreases. That means that the external pressure (due to the Earth’s atmosphere) will push the covers onto the glass wall.
Actually, this force from the atmospheric pressure can be quite large. The pressure is . So if the pressure inside the covers is just half an atmosphere with a radius of 10 cm, then the net force (for the two covers) would be:
That’s some serious force. But wait! This is not the force that supports MacGyver. In fact, it is the frictional force between the cover and glass that keeps him from falling. The frictional force is an interaction between two surfaces that acts parallel to the surface. It depends on two things:
The types of materials interacting.
The magnitude of the force that pushes these two surfaces together.
If you push two surfaces together really hard, there will be a greater frictional force. So, this force from the vacuum cleaner exerts a force that increases the frictional force and this frictional force allows MacGyver to climb like Spider-Man.
Here is something similar with a guy that hangs from an overhang with a vacuum cleaner. Pretty cool.
This is real (based on something real). Yes, you can actually make metal things smaller. Here is a great video from Physics Girl (Dianna Cowern) that shows how this works.
The basic idea is to create a HUGE electric current very quickly. This large change in current can create a very high change in magnetic fields. When you put metal in this high changing magnetic field, it induces an electric current in the object. This induced current creates a magnetic field that interacts with the external magnetic field in such a way that the device gets squished. It’s awesome. Oh, when I say “a large change in magnetic field”, I am actually talking about the time derivative of the magnetic flux.
So, what do you need to make this coin shrink thing work? You just need super high current super fast. The best way to do this is to charge up some big capacitors and then discharge them through some wires. That’s essentially what MacGyver does.
The biggest problem is his capacitor. He builds one using two roulette wheels. Like this.
Yes. Any two metal devices can create a capacitor—but you want one with a large surface area and very close together. If you turned the two tables around so the flat side was close to the other one, it would be better—but it’s still a capacitor (but not really big enough for this job). Still, the idea is solid.
This is an offensive weapon called an Electromagnetic Pulse (I guess the M is in there too). The idea is to generate a short, but very high intensity electromagnetic wave.
There are all sorts of EMPs, but let’s consider the one that you are mostly likely familiar with—a lightning strike. Have you ever had lightning hit near your house? If you have, you might find that some of your electronic devices no longer work. That sucks, doesn’t it?
Mostly likely what happened was a spike in the electric current in the house. When the lightning strikes, it makes a very large change in magnetic field (associated with the giant current from the bolt). This changing magnetic field can create an electric current.
Check this out. I have a loop of wire and a magnet. As I move the magnet into the loop (or out of it), a current is created.
That’s sort of what happens with your house. But what about the EMP? Same idea—except MORE change in magnetic field. It’s possible to make an EMP that is strong enough to take out the circuits of a bunch of things. Yes, like a plane.
Is it possible to make an EMP that’s handheld? Yes, that’s possible—but it wouldn’t be super strong. Bigger is better.
I had no idea that “the thing” existed—at least not until the awesome MacGyver writers told me about it. I read the script and said.
What. What? WHAT? Is this real? How did I not know about this? What the heck!
The basic device consists of a conducting cavity with a membrane. When a particular microwave frequency is aimed at the device, sound will move the membrane and change the reflected wave. The change in the reflection will be interpreted at sound. This site has a much more detailed explanation.
OK, but could MacGyver build one? Yes. Especially in the Phoenix lab. Honestly, I was going to build one for fun. However, it’s tricky to get the size and stuff just right in order for it to work. It would be fun to build a working model though.
Sadly, this is all too real. Yes, you can indeed hack a car.
Older cars don’t have computers in them. You can’t hack plain metal and gasoline.
Pacemaker from a phone and an amplifier.
Could you hack someone’s pacemaker? Probably not—but it’s at least possible. My first guess is that you wouldn’t have any type of network connection on your pacemaker, but maybe you would. What if you want to modify how it works without actually taking it out of the human body? In that case, you would have to communicate with the pacemaker somehow—right?
OK, so the dude got hack. He needs a temporary pacemaker. MacGyver takes some paperclips to use as electrodes and connects them to the car’s audio amplifier. He then generates a 1.7 Hertz audio signal with his phone. The idea is that the audio “sound” generates electrical signals that stimulate the heart into work.
Would this actually work? Maybe? Honestly, I wouldn’t want to try this in real life.
I’m kicking myself. I should have been writing these MacGyver notes for each episode as they aired on TV. But no. I had to make things more complicated. Well, here I am—starting the notes for season 2.
Let’s just jump in. Note: there’s some pretty good stuff in this one.
Blade from a button.
MacGyver takes a button from his shirt and breaks it in half. From this half button he sharpens the edge so that it can cut through a rope.
I wouldn’t normally include this one in the blog since there’s not much science to talk about—but I’m just excited.
Flare-based harpoon and winch.
MacGyver takes a metal rod and puts it in an empty dip stick tube from an engine. He adds the powder from a road flare to act as a propellant. This would then launch the improvised harpoon forward.
Once the harpoon is stuck into a fleeing car, Mac wraps the cable around the horizontal axle on the sidecar to a motorcycle. As the axle spins, the cable wraps around it and pulls the motorcycle closer to the car.
Mini gun as a starter motor.
They need a car. MacGyver finds one—but it’s missing a starter motor. Really, there is nothing super special about a starter motor. It’s just a DC motor that is strong enough to turn over the engine so that it can turn itself (using gasoline).
The mini gun also uses an electric motor. In this case, the motor spins a combination of gun barrels so that the fire rate can be higher than a normal machine gun.
Could you use one motor for another application? Theoretically, yes. The only tough part might be mounting the motor (which MacGyver does with some wire—wire is often better than duck tape). The other problem is making sure the gears on the motor match up with the gears on the car to turn over the motor—but it’s still possible.
Run up a wall with a pole
Sometimes, there are hacks that look too crazy to be true—but in fact would totally work. Here is an example of such a hack.
MacGyver and friends take a long pole. MacGyver gets on one end near a wall and the other two push the pole towards the wall. This allows MacGyver to walk up the wall.
But wait! Here is a video of this trick being used in real life by a Vietnamese SWAT team.
Here is my super short explanation.
If you push someone against a vertical wall, there will be a frictional force pushing UP.
If the push is great enough, this upward frictional force can be equal to the gravitational force.
Boom. That means a person can walk up a wall.
Here is a force diagram of that situation.
Oh, I also made a video to show you how this works.
Just to show you what that was like, here is an older picture of me. It’s not cave diving, but it’s using all of the same gear (it was practice).
Let’s start with the scuba gear. MacGyver doesn’t have a regular scuba tank, so he uses an oxygen tank used for welding. You don’t normally want to use oxygen for scuba—you want to use air (which is only 21% oxygen). You see, oxygen is actually toxic. If you breath oxygen at high pressure, it can do bad stuff to you. Fortunately, MacGyver is going to use this at very shallow depths—he should be fine. Also, he won’t need to much gas as you consume much more at greater depths (for open circuit systems like scuba).
What is a regulator? Suppose you have a pressurized tank at 1000 psi. You can’t really breath air (or any gas) at that pressure (although there are some tricks—ask me later and I can tell you about this). That’s where the regulator comes in. It takes pressure from the tank and reduces it to the ambient pressure. That’s really important. It has to deliver the pressure at the same pressure around the human. If it was too low, you wouldn’t be able to expand your lungs and breath.
Luckily, they have regulators for welding stuff too. You need a second regulator to let air out only when you breath—but it’s possible to build one of these (they are much simpler).
Now for the DPV. These things are very useful in cave diving. How are you supposed to get 5,000 feet back in a cave if you have to swim the whole way? The early DPV (or scooters as we called them) were essentially trolling motors from a bass fishing boat connected to a battery.
Just about any electric motor with a battery could work. Ideally, the motor should be sealed so it can run underwater—but it doesn’t have to be perfect. It only has to work for a short time.
I really like the scooter in the episode. It really looks like a home built scooter.
OK, you can’t see it too well in that image—just trust me. Or better yet, watch the episode.
I also like how MacGyver side mounts his tank. Even if you have done normal scuba diving, you might be surprised at how these tanks behave underwater. Just because they are heavy out of water doesn’t mean they will pull you down underwater. Very often we would bring extra tanks (stage bottles) in a cave and carry them on our side just like MacGyver did.
Parkour Wall Jump.
MacGyver gets to run up a wall twice in this episode. Just like the wall run with the pole, this case also uses friction. It’s your classic parkour wall run-jump.
If you run towards a wall and push yourself back, there is a force between you and the wall. The faster you run, the greater the force. If this force is great enough, there will be a large enough upward frictional force so that you can get an extra upward jump.
When I think about the physics labs I teach, I realize things have changed over the past 18 years. The way that I run introductory labs is different than when I first started. Here is a review of my lab philosophy over the years.
I’m going to leave off the labs I taught as a graduate student since I wasn’t really in charge of the lab design.
Phase 1: Mostly Traditional – But With Computers
Really, when you first start off with a tenure track position you have to go with the flow. You can’t jump in and start doing crazy stuff. There are too many other things to focus on (grants, papers, projects…). So, for me—I just took the departmental physics lab manual and started with that. It was pretty traditional.
But I quickly set out on my own. I stopped using the lab manual and made my own labs. Oh, they were still pretty traditional in the format of:
Here is some physics theory.
Here are detailed instructions on how to collect data.
Here are detailed instructions on how to analyze the data.
However, my labs had data acquisition stuff to make it cooler. I found some money to put new (at the time new) iMacs in the room and used Vernier Logger Pro with sensors and stuff. Wait, I actually have a picture of this room from 2003.
Check that out. Those are some classic iMacs. Those suckers were in use for at least 10 years.
There was another important aspect of this “phase 1 lab”. I wanted to have the students work on the following:
Error analysis (uncertainty)
Technical writing and communication
Note: you can not do this many things. It’s either a 2 or 3 hour lab. At most you could focus on two of these things.
In terms of writing, I think I was making excellent progress on this front. I was working on an idea about peer evaluation of writing. The basic idea is that students evaluate other students writings as a way of helping everyone write better. I still think this is a good idea, but I moved on (because of many issues and other things to work on).
Phase 2: Make Pre Lab Great Again
If you have taught labs, you know that students aren’t always properly prepared. Most faculty know this. They might spend the first 30 minutes of lab time with a lecture to cover the important points. But this still doesn’t work. It’s hard for the students to pay attention and to fully grok the lab. They end up just asking questions about stuff you just told them.
OK—I can fix this. I will just make super awesome lab materials and post it online. Note only that, I will include videos and everything. Students will look at this and then we can just rock and roll during lab.
Nope. That doesn’t work. It doesn’t matter how great the video teaches the concept if students never watch it. In fact, I would find many students watching the video IN LAB. This drives me crazy—mostly because I hate hearing my own voice.
I tried online pre-lab quizzes. That didn’t work. They would just do the bare minimum to get the stuff done before class. It was just a pain in the rear.
Oh, what about pre-lab quizzes in class? Again, those are more trouble than they are worth.
Phase 3: Play and Compete
This one works fairly well. Forget about the pre lab stuff. Drop the lecture at the beginning of lab too. Give the students stuff to play with and see if they can come up with their own questions.
Here is an example in the realm of 1-D collisions.
Show students the tracks, carts, and different bumper options.
Tell them “keep the track level”, but otherwise just play with it.
Students love the magnetic bumpers. Many of them will try collisions between different mass carts.
After they have played, suggest they try to calculate the kinetic energy and the momentum of the carts.
Let them come up with their own methods for calculating velocities (I give some options).
That works fairly well. Some students don’t do too much, but for the students that find cool stuff it works great.
Here is another example with a competition. Again, no pre-lab.
Show students an inertial balance (oscillates back and forth).
Let them play with it.
Now for the challenge. Can you use this to find the mass of 4 unknown masses? The quiz at the end of the lab is just finding the mass. Your score is based on your accuracy.
This works fairly well—but not every lab can be in the form of a contest. However, students love to compete and it’s fun.
Phase 4: Free-for-all
This is where I am at now. I don’t expect students to prepare for lab because I will just be disappointed. The labs are a combination of all types of lab. Sometimes they are just verifying an equation. Sometimes they get to build stuff. I don’t expect the lab to match up with the lecture course (because apparently that doesn’t matter).
Sometimes labs still suck, but sometimes they are awesome. I will keep changing my labs until everything is perfect.
Really, I’m just answer this question from Twitter.
Honestly, this is what I love about working with the MacGyver people. It’s great that they even care enough to bring in a science consultant (that’s me) to look at the MacGyver hacks.
So, I will start off by saying this. Pretty much all of the hacks are at least based on some real scientific idea. None of them are just magic.
In fact, you could go through all the Mac hacks and rate them on a scale from 0 to 10. 10 would be a hack that is one hundred percent legit—totally real. 0 would be magic. Like I said, there are no zero’s that I can recall.
How about some examples from previous episodes with some reality scores?
Score = 8: DIY dog whistle. It might take some messing around to get it to work just right, but it’s basically legit.
Score = 7: Hot air balloon for you phone. Yes. You can totally make a hot air balloon. It’s not even hard. The problem is the lifting capacity. If you want to a balloon to lift a phone, it’s going to have to be fairly big.
Score = 5: Pick a lock with a paper clip. The idea is right, but I really doubt you could use a normal paper clip unless it was a super sucky lock.
Score = 3: All the explosions. When you mix two or more chemicals together, bad stuff can happen. Often the effect size is smaller in reality and often the time to set these things up is quite long. Don’t make explosions.
Score = 2: Disabling a car with some electromagnetic thingy. MacGyver builds some devices to stick under cars to prevent them from starting. Yes, starting a car deals with lots of things working together, so you just have to disrupt one of these things. If you have an electromagnetic oscillation (from the device), it could interfere with the computer or maybe even the spark. It’s a stretch, but it could indeed work.
What about a score of 1 or 0? I’m sure they are out there, but I don’t have any that come to my mind. What about the average score? If I had to guess (apparently I do), I would say a score of 6 would fit pretty well.
MacGyver pulls a feather out of his jacket and uses this to detect air currents. This should work since the feather will move due to super tiny air motion that would be too small for a human to feel.
This reminds me of a job I once had. The job was to go to people’s swimming pools and find leaks. I would take a small squeeze bottle with red dye and let out tiny amounts into the water to see what would happen. If the red dye got sucked into the wall—there’s your leak. Oh, this was done with scuba gear so that I could stay underwater for long periods of time. It was extremely boring.
Finding position from a smartphone accelerometer
Your phone has an accelerometer (probably). At the very least, this accelerometer is used to determine the orientation of the phone so that it knows if you are taking a normal video or a vertical video (don’t do vertical videos).
This accelerometer is essentially a tiny mass on a spring (but not an actual spring). When the phone accelerates, the spring gets compressed by an amount that is proportional to the acceleration. That’s how you get the acceleration. Once you have the acceleration, you can integrate twice to the get the change in position of the phone (assuming the phone started from rest). If you keep doing this every tenth of a second (or whatever time frame you want), you can track the location of the phone. True.
In fact, if you use the augmented reality (AR) on your phone then you have to use the accelerometer. Your phone figures looks at a surface from different viewpoints to figure out how far away it is. The different viewpoints are determined by the motion of the phone and the accelerometer.
Just because it’s cool—here is my short explanation of AR on the phone.
Can you actually make a toxin from a pea seed? Yup. That’s possible. In fact, there are a bunch of things out there in the real world that have some pretty deadly stuff in them. Here are some options.
If you have a normal wifi antenna on your computer (and you probably do), it basically just transmits radio waves in all directions. It’s not a completely uniform signal strength in all directions, but let’s just assume it is.
Imagine these radio waves expanding out and forming a sphere. Since the area of the this radio wave sphere is proportional to the square of the radius, the signal power decreases with distance. That’s just how it works.
But wait! What if you redirect these waves into one direction? That would increase the radio power along that direction and give you a better signal. However, you now have to aim this thing.
There are several methods to make a directional antenna. The two common methods are to use a parabolic dish (like a satellite dish) or a wave guide. The wave guide uses a tube with an antenna located at a certain point. Waves go down the tube and then reflect to constructively interfere and make the signal stronger in that direction.