Week 5 - How can we design a safe and durable playground surface?

Lab: 

    This week in lab we finished up our investigation on why we need to push a child on a swing to keep them going and how if they don't have a push, eventually they will run out of energy. We used a pendulum simulation to explore this idea more and noticed that the thermal energy or friction is what is slowing the pendulum down. We used an air particle model of the pendulum colliding with the air particles around it and discussed that as the pendulum collides with the air particles around it, it speeds them up while slowing the pendulum down, transferring energy from the pendulum to the air. 

    We then moved on to our last investigation of the physics module, how can we design a safe and durable playground surface? The first thing we did was use the engineering design process, and explored at all the different materials people have already used to create these surfaces. From those ideas, we gathered materials and began brainstorming with our groups as to how we wanted to design our surface so that it could prevent an egg from cracking when dropped a meter from the surface. We ended up using saran wrap, hay/straw, and the rubber mulch to cushion the fall of our egg. We came to the conclusion that too much force is what breaks the egg. In order to create a surface that doesn't break the egg, we had to increase the amount of time the egg takes to slow down. In our video, we noticed that not only was the egg affected by the impact but the surface was too. As the egg struck the surface, the energy transferred from the egg to the surface. The surface then compressed and sprung back transferring the energy which is now kinetic, back to the egg.