 Welcome back to Kids Fun Science. My name is Ken. Today's experiment is Leonardo's Arch Bridge. What you need for this experiment is 18 paint stir sticks. You can get those at a local paint store and a hardware store. So starting this off, I'm going to show you how to do it through this little video, but at the end I have some still shots to show you step by step and taking you all the way through 11 steps on how to do it. So you can see you have to kind of very carefully lift up and you know kind of sort as you go and you can see a lot of the bridges are right there. You're going halfway. You go under and then halfway on to the next step. So there's no glue nails or anything holding it together. Only thing holding it together is friction itself and the pure weight of the bridge. So you can see everything's there. You lift it up gently and you can see it goes halfway in between and the bridge is complete. The science behind this is modern bridges are built with high strength materials and carefully selected fasteners. Design considerations include the weight of the bridge, the load it carries, as well as the stress caused by wind and earthquake. Bridge components are subject to tension, compression and other elements. Leonardo's Arch Bridge is amazing because the design is self-supporting requiring no fasteners. Leonardo's envisioned using nothing but large logs to build the bridge. The bridge own weight holds it together which is pretty cool. As the weight is added to the bridge its structural elements are forced more tightly together making it even stronger. Norway actually has the Vinci Bridge which is a pedestrian over crossing that opened in 2001. It's loosely based on the 15002 sketch that is used by steel and wood instead of mason-dury blocks. So cool about this is just a series of wood beams holding it together. There's no nails, no screws, no ropes, no glue, no notches, no fasteners holding the bridge in place, just friction and gravity. Okay so just to show you here if I push down on it that it's going to support the weight but when you pick up one piece it just all falls apart which is pretty cool. So there's nothing holding it together besides friction and gravity. Here are the next steps the set 11 steps if you want to go through step by step so you can see what you're doing and I hope you enjoy this video and remember to click thumbs up and subscribe and thanks for watching.