Pringles Chip Activity

One final activity we did to wrap up Civil Engineering involved an American favorite, Pringles! Little did I know before doing this activity that the "saddle" shape in which the chips are formed is quite significant. Although most people aren't building a Pringles ring with this snack food, the shape of the chip prevents the chip from breaking when sliding out of the cylindrical package. The Action Lab does a good job explaining the science behind why this works and gave us a starting point on how to start our own Pringles ring.

One final activity we did to wrap up Civil Engineering involved an American favorite, Pringles! Little did I know before doing this activity that the "saddle" shape in which the chips are formed is quite significant. Although most people aren't building a Pringles ring with this snack food, the shape of the chip prevents the chip from breaking when sliding out of the cylindrical package. The Action Lab does a good job explaining the science behind why this works and gave us a starting point on how to start our own Pringles ring.

The Shape: Hyperbolic Paraboloid

As shown in the photo above, a hyperbolic paraboloid is a parabola that is pulled out into 3D with hyperbolic cross sections. Curves generally add strength to structures, which is why it's common to see roofs shaped like this (see below). Corrugated cardboard or other material is another example of how engineers take advantage of the strength in curvature. Because it handles tension and compression so well, the unique shape of this chip (hyperbolic paraboloid) makes for a sturdy snack food which limits breakage. The picture below shows the parts under tension in black and the parts under compression in red. Its double curvature (both concave and convex) helps it balance these two forces in such a way that even built thinly can withstand quite a bit of weight.

For more information, you can visit https://www.wired.com/2014/09/curvature-and-strength-empzeal/.

How it works:

We successfully constructed the Pringles ring although it could have looked a little more aesthetically appealing. It began to lean to one side, but we managed to add the final chip on top before it toppled. We took advantage of both the center of mass of the chips and friction to gradually curve the sides upwards and eventually complete the circle. As long as we didn't put the chip past the center of mass of the bottom chip, the top chip would not fall over. We also used frictional force to combat gravity. The pushing force the chips exerted on each other kept them from sliding down. Here are some pictures we took along the way:

Examples of this "saddle" shape in buildings:

Felix Candela's Ciudad de Las Artes y Las Ciencias:

London Velodrome: