The hopper project in Design Nature is the first project at Olin. Given a very limited set of materials, we are asked to make a hopping toy inspired by nature. My toy, shown above, hopped about two feet, but the interesting piece of it was the physics behind why it hopped. Rather than use feet-like pieces to push off of the ground, my design relied on shifting the center of mass. The hopper consists of three circles, but the outer two are tied together, so from the side there are two circles which rotate away from each other, causing the hopper to flip itself over. If the circles were solid discs, nothing would happen, but because the upper half of the circles are empty, the center of mass starts below the center of the discs, then moves up when the hopper flips, creating upwards momentum which causes the toy to hop. We also need to have a delay mechanism, so the hopper wouldn't hop immediately after releasing it. I solved this with an ice rod, which is placed through the three upper holes, locking all three rings together, until the ice melts enough that it shatters, and the hopper releases (see video below).