Combining Solid Shapes to Build Towers, Bridges, and Houses

Look for this idea outside of your lessons. Every building on your street reflects choices about which shapes carry weight and which do not. This is worth learning because shape decides what can be built and what will fall over.

Watch for it today, and when you spot it, tell someone what you noticed and how you knew. Ask yourself where else the same idea might be hiding, then go and look.

Let us think about this slowly. Solid shapes stack and join. Cubes and prisms stack well because their faces are flat. Spheres roll away, so they make poor foundations.

Cylinders stand steady on end but roll on their sides. Build a tower and notice which shapes hold and which slide. Builders make these same choices, which is why you see square blocks in walls and rounded shapes used for other jobs.

Try building the same tower twice, once with cubes on the bottom and once with a sphere on the bottom. The experiment answers the question faster and more convincingly than any explanation could. Show your work to someone and explain it in your own words.