Building Marshmallow and Spaghetti Towers

Building marshmallow and spaghetti towers is a fantastic way to explore the physics of forces and the limitations of different construction materials.

• Spaghetti: Spaghetti can handle a fair amount of force travelling down the length of the strand (compression), but it will quickly snap if it is bent or twisted. Because it is brittle, you must consider how force is transferred through each strand. You likely found that arranging your spaghetti into triangular shapes produced the most stable structure. This is because triangles are the only polygon that cannot be deformed without changing the length of one of its sides, making them the foundation of nearly every major bridge and skyscraper.
• Marshmallows: Marshmallows are gooey in their centre, which means they can be easily torn if a shearing force is applied. They act as the “nodes” or joints of your structure. You would have also found that marshmallows introduce a mass distribution problem—too many marshmallows on one side and the tower’s centre of gravity shifts, causing it to topple!

Applications

Understanding how forces flow through a structure is critical for engineering. These days, complex computer modelling is used to test the effect of different structural arrangements and material types to determine the optimum design of a building before a single brick is laid.

Every material has a known breaking point, and different arrangements of these materials produce different patterns of compression (squishing together) and tension (pulling apart). If a design isn’t balanced to handle these forces, the structure is at risk of catastrophic failure. This is why engineers use “truss” systems—interconnected triangles—to distribute loads evenly across a wide area.

Variables to explore

Find out more on variables here.

• Adhesive Quality
  Try different brands or ages of marshmallows. Do “stale” marshmallows provide a stiffer joint than fresh, gooey ones?
• Structural Reinforcement
  Would binding multiple spaghetti strands together with tape increase the strength and the ultimate height of your tower?
• Binding Materials
  Try using jelly babies or Blu-Tack as the binding material instead. Does the increased density of these materials make the tower more stable or more likely to collapse under its own weight?
• Environmental Factors
  Does it matter if you build your tower on a cold or hot day? Consider how humidity might affect the “snap” of the spaghetti or the “melt” of the marshmallows!