STEAM: Structural Engineering with Snacks

Have you ever been told you shouldn't play with your food?

Perhaps you shouldn't play with dinner, but have you tried building with snacks? It's tasty, and you can learn about structural engineering. This area of engineering designs human-made "structures." Can you name a few? Good examples are towers, buildings, bridges and walls.

To become a structural engineer, you'll learn how to design the "bones and joints" that create these structures. You'll learn about stability and how a structure handles natural disasters like earthquakes and erosion.

Let's focus on one area of human-made structures—bridges. A bridge is a structure carrying a path over an obstacle (such as a river or road). In the United States, there are over half a million bridges. They vary in size, purpose and materials, but they are all stable enough to withstand natural disasters.

Bridge engineers must consider the distance and materials before deciding on the size, shape and appearance of a bridge. Since ancient times, engineers have designed four major types of bridges.

The beam bridge is an early type. It has a horizontal beam supported at each end by piers. The weight of the beam pushes down on the piers. The farther apart its piers, the weaker the beam becomes.
The truss bridge uses wooden or metal triangles, known as trusses, to give the bridge its stability. The triangles allow this bridge to support considerable loads over a larger distance. They use a relatively small amount of material for the weight they can support.
The arch bridge supports weight through compression. With weight pushing down on the arch, the pieces push into each other. This style was historically built with stone and famously used in Roman architecture.
The suspension bridge uses overhead cables to support its roadway. These modern bridges are lighter-weight and can span longer distances. They are the most expensive to build.

Now, use your bridge knowledge to be a structural engineer and enjoy a snack with this activity from Washoe County Library System.

Snack Bridges

Consider what you have learned about bridges. Just like an engineer, start with a plan and sketch your design. Modify along the way as you discover what works well and what doesn’t.

Supplies

Snacks (marshmallows, grapes, apple pieces, cheese cubes, bread cubes, gumdrops)
Thin pretzel sticks or toothpicks
Small toy figures, toy cars, small blocks to use as test subjects

Steps

Explore your supplies and make some test shapes. Try some different snack combinations. Which materials are strongest? Which ones are weakest?
Select your building (and snacking) materials, then build your bridge.
Test your bridge to be sure it is stable—that it can stand without collapsing.
Test the integrity of the bridge with the help of your test subjects. Structural integrity is the ability of an object to hold together under a load, without breaking or deforming. Roll your test subjects across the bridge. Is it still standing? Does your bridge have structural integrity? If so, then congratulations! Have a snack to celebrate. If not, have a snack anyway. You’ve earned it. Then go back to the drawing board to redesign and try again.