Oreos and π
This is a short and uninteresting post. It seemed interesting when I first thought about it, but like a lot of things, on hindsight, it's just a given. Still, I would like to share it.
This week while stuck in camp, I took out a pack of Oreos I brought in and started snacking on them.
Have you ever had Oreos before? A common packaging is the cylindrical ones, with 11 cookies in them.
I suspect that it's a prime number of cookies because they want to make it hard to split evenly with a positive integer amount of humans, so consumers would have to purchase more packs to share evenly. But this post is not about number theory, so we'll move on.
The package looks like this, and I let the width of the cylinder be 2r. This is essentially the diameter of the oreo cookie.
After gluttony takes over and I finished the entire pack myself, I flattened the wrapper and prepared to throw it out, and then I noticed something interesting.
I just converted a 3D object into a 2D one. Well, that is true if we disregard the thickness of the foil wrapper. So I looked at new width of the wrapper, now that I have deformed it into 2D.
Simple calculations tell us that the width is now πr. I thought this was interesting because it provided a new way to multiply by π/2.
After that, I thought, if the packaging were torn through cleanly to produce a single sheet, then the width would be 2πr, more recognisable, because this is the circumference of the cylinder, or, the circumference of the Oreo cookie.
Still, this is an interesting but non-practical way to multiply a number (more precisely a length) by π/2. We can wrap a piece of paper around the length as the diameter, and fold and flatten it. It's quite simple.
Now that I think about it again, of course Oreos had to be related to π somehow. It's a circle. We defined π based on it.
==Endnote==
I don't own a vernier caliper, which I believed would be sufficient to measure the thickness of the Oreo wrapper. Turns out, a vernier caliper would have been useless, because research suggests that the thickness of the wrapper are in terms of tens of microns, and the maximum thickness is about 0.2mm, or 200 microns.
The coating of aluminium on the interior for insulation is given in terms of Ångström. The lining is about 500Å - 600Å thick.
