Drag from an orange anchor (or any joint) to a dot to build a beam. Beams can be up to 3 squares long.
🔺 Triangles vs. ⬜ Squares
Press Push! to shove the top of each shape sideways. Which one keeps its shape?
Why do triangles work?
A square's corners can bend like a hinge, so it squishes into a slanted shape (a parallelogram). But a triangle's three sides lock each other in place. You can't change a triangle's shape without making a side longer or shorter! That's why engineers call triangles rigid.
A bridge made of many triangles is called a truss bridge.
🌉 Kinds of bridges
Beam: a flat road resting on supports. Simple, but only for short gaps.
Truss: a frame of triangles, strong and light.
Arch: a curve that pushes weight out to the ground on each side.
Suspension: the road hangs from cables on tall towers, like the Golden Gate Bridge.
🏜️ Near Las Vegas, the bridge next to the Hoover Dam is a giant concrete ARCH bridge, high above the Colorado River!