The Materials Test & Hooke's Law

The first step in determining what to use for our bridge was a rather easy experiment involving Hooke's Law. Hooke's law is defined as F=-kx, where F stands for force, k is the spring constant, and x is displacement of the spring. This illustration demonstrates the law most accurately:

Basically, Hooke's Law is used to determine how much force it will take to make something stretch a certain distance from it's original point on an imagined Cartesian Plane. With this in mind, we used a force measurement tool to see just how strong each of the materials was. We did this by extending them across a gap and pulling down on them with an apparatus that measures how many newtons of force it takes to actually snap the material in half, or otherwise break it to the point at which it is unusable. As a result, we were able to determine that it took 21 N of force to break a bamboo skewer, and 3 N of force to break a coffee stirrer. Though we were unable to get the data for the toothpicks because we ran out of time in class, we can conjecture that they would be somewhat stronger than the coffee stirrers but nowhere near as strong as the bamboo skewers, mostly because the bamboo skewers had a large elasticity constant, meaning they were able to stretch far more without breaking. On the other hand, in casual observation one can tell that a toothpick does not flex even remotely as much as a skewer can, and therefore it would break far more easily.

To make a long story short, bamboo skewers were by far the best material to use in regards to strength, while the other two materials trailed far behind and had similar strength and elasticity.