Name_____________________________ Name _____________________________ Date ________________ Arches Have you ever seen an arch? An arch looks like an upside-down U. The arch has been used in structures for centuries. Arches help support bridges and gateways. They’re used for doors and windows and for holding up ceilings, roofs, and floors. Arches are still used in many structures today. Let’s investigate how to build an arch and how its shape helps to make it strong. Build arch model 1.1 in building booklet 1, but stop at step 1. How many levels of bricks are across the center of the arch? __________________________________ Stand the arch up. With your fingers, press firmly on the center of the arch. What happens? ______________________________________________________________________ Repeat this experiment with one partner holding the bases of the arch. What happens? ______________________________________________________________________ Why? ______________________________________________________________________________ Continue building the arch to step 2. How many levels of bricks are across the center of the arch now? _______________________________ Stand the arch up. Press down firmly on the center. What happens? ______________________________________________________________________ Which arch model was stronger? first one second one Why? ______________________________________________________________________________ ____________________________________________________________________________________ ____________________________________________________________________________________ Now let’s explore how arches can work together. Begin building model 1.2 in the building booklet, but stop at step 1. At this point, your model should look like a Y. Place your Y-shaped model upside down on your table. Press down firmly on the middle part of the model. What happens? _______________________________________________________________________ Continue building through step 2. Place the model upside down again and press down on it as before. What happens this time? _______________________________________________________________ Why? ______________________________________________________________________________ Finish building the model. Stand the model up. Press down on the model at different places along the top. Observe closely. What do you notice? _______________________________________________________________________ ____________________________________________________________________________________ ____________________________________________________________________________________ What You Have Learned When you press down on the center of a fully built arch, what do you expect will happen? If you have more time, investigate arches further. What is the tallest arch you can make? The widest?