# How do you deal with the density of gold in TV shows and movies?

It felt like it went on for a couple of weeks. I kept getting the same promoted tweet on twitter (I can’t even find it now). It was an ad for the show Money Heist on Netflix.

I really don’t know much about the show, but the ad shows some people scuba diving inside of a flooded vault and picking up some gold bars. Like this.

# How Much Would It Cost to Move the Earth and Fix Climate Change?

I wish I could say this wasn’t true — but it’s true. A congressman proposed the following idea: what if we could fix climate change by moving the Earth’s orbit?

I told you it was true. Check it out.

Yes, it’s a crazy idea (for multiple reasons). However, we can’t let crazy get us down. Instead, let’s use this as a basis for an awesome physics problem. Here it is:

Suppose you move the Earth such that the intensity of light from the Sun decreases by 1 percent. How much energy would this orbital change require? …

# We Shouldn’t Avoid the Unit Vector in Introductory Physics

There is a problem with many of the algebra-based physics textbooks (and courses) — they avoid unit vectors and maybe they shouldn’t.

Oh, what is a unit vector? How about I start with a physics problem so you can see why we need unit vectors. Don’t worry, I’m going to still give my full explanation of unit vectors.

One of the first topics in the second semester of physics is that of electric fields. If you have a positive point charge, the electric field would look something like this.

# Lagrangian Example: Sliding Bead on a Rotating Hoop

I don’t know who came up with this problem, but it’s actually pretty fun. Here’s the deal:

• Start with a hoop with a radius of 0.05 meters. It rotates about an a vertical axis (in the y-direction) that passes through the plane of the hoop (see the sketch above).
• The hoop rotates with a constant angular velocity of 10 rad/s.
• On the hoop, there’s a bead with zero friction such that it can slide along the hoop. Let’s say it has a mass of 0.05 kg (but of course the mass doesn’t actually matter).

So, let’s find an equation of…

# Numerical Surface Integrals in Python

Let’s say you wanted to calculate the area of a circle. Oh, I know the answer already, but let’s just pretend. Also, for fun suppose you want to do this numerically by breaking the circle into many tiny pieces and finding the sum of the areas of the pieces. How would you do that?

I’ll be honest. I don’t want to find the area of a circle. I want to find the magnetic flux through a circle for a complicated magnetic field. This means I’m going to use a numerical calculation to find the magnetic field at a bunch of…

# MacGyver Science: Abduction + Memory + Time + Fireworks + Dispersal

I remember binge-watching the show Parks and Recreation with my youngest son. It was great. But then we got to the last episode and he said he didn’t want to watch it. If we watch it, then it will be over. That’s how I feel about this episode.

Note: don’t worry — I still have a bunch more MacGyver stuff. I’m working on my paper clip videos (building stuff using paper clips). You can see those here:

Now for the science in this episode.

The Drake Equation and the Fermi Paradox

It’s not really a MacGyver-moment, but it’s an…

# What Are All These MacGyver Equations?

For the first episode of Season 4 (Fire + Ashes + Legacy = Phoenix). It starts off with all the members of the team from the Phoenix foundation doing their own thing. Riley does computer support, and Bozer is making a movie — but MacGyver has picked up a job as some type of adjunct lecturer at a university.

OK, let’s go ahead and talk about this academic position. Could Angus be a professor? Probably not. For most institutions, a professor would be a tenure-track position (able to earn tenure). This includes the academic ranks of Assistant Professor, Associate Professor…

# 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.

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. …

# Modeling a Spinning and Flipping Handle Using Springs and Python

I don’t think that title really explains the problem. It’s called the Dzhanibekov Effect — but that doesn’t really help either. How about this? Imagine you are in the International space station and you unscrew a t-handle really fast. Once the handle leaves the thread, it’s just floating there and spinning. Then this happens (here is the YouTube version):

# MacGyver Science: Barn Find + Engine Oil + La Punzonatura + Lab Rats + Tachometer

DIY Epoxy Putty

MacGyver, Riley, and Bozer are on a ship — and that ship is in trouble. It’s sinking. In order to seal some leaks, MacGyver makes some epoxy putty. He uses: olive oil, sand, epoxy resin, and shampoo.

He’s actually trying to make something like this epoxy putty.

Here is a DIY putty (clay) that is similar.

But the bad news — it doesn’t work. Something went wrong.

What Went Wrong?

MacGyver is trying to figure out why the epoxy putty failed. If you’ve watched the show, you know the reason. He’s losing feeling in his hands…

## Rhett Allain

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

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