# Pringles, Einstein, and Hyperbolic Paraboloids

One year in a Physics class, I had a student who ate a tall can of Pringles at least three times a week all year. I will leave the arithmetic of that off the table for now, but after reading a blog post from Freakonomics called The Math of Pringles, I absolutely must discuss this unusual snack.

What’s the difference between Pringles and regular chips? This is an easy one. Pringles are engineered to be (more or less) congruent to all other Pringles. Potato chips are (more or less) cross sections of actual potatoes, which gives them more variety of shape.

Pringles are popular, too. According to the Wikipedia Page for Pringles, they are sold in over 140 countries, with over \$1 Billion in sales annually in the United States alone.

But, what the heck is the deal with that shape? With the recent trend toward natural foods, foods whose shape is so carefully designed might seem to lose steam. But let’s take a closer look at the carefully-designed shape.

If you examine the saddle-shaped look of a Pringle, see if you can notice that two opposite sides are both pointing down, and the other two opposite sides are both pointing up. This kind of shape is called a Hyperbolic Parabaloid and, according to the video post by Freakonomics, such shapes are rooted in Einstein’s Theory of Relativity, which states that space has a natural curve (among many other things). His theories led to the development of non-Euclidean geometries (that is, geometry that is not done on a flat surface… imagine graphing lines while drawing on a basketball.)

Why do you suppose such an unusual geometric shape was chosen for Pringles? What are your experiences with Pringles? Do you like them? What does the shape of the chip do to the experience of eating them?

Discuss these points in the comments.