Engineering the Pointy Roof: From Flat Circles to Cone Tents

This activity begins with a story. Teacher shows a short video of a mouse caught in the rain. In the video, the mouse finds a cone tent, but it is too small for her to fit inside. This builds immediate empathy. You then place a real 7 cm toy mouse on the table. "Maisy is cold. She needs a tent."

Students must transform flat, 2D paper circles into 3D shapes. They cut along a single straight line and fold the paper using a pre-creased fold. When they secure the edges with tape or glue, the flat circle becomes a 3D cone. They test if the 7 cm toy mouse fits inside their new 15 cm tent.

This is where the surprise happens. The 15 cm cone is too tight. Some students will try placing it sideways on the table to push the mouse in. A sideways cone rolls away. A narrow cone leaves the mouse exposed.

Do not rescue them. Let their tents fall over. Failure is the core engineering lesson here.

As students iterate, they test circles of 18 cm, 20 cm, and 22 cm in diameter. Each size is printed on a different colour of paper to make comparing them easy. Students discover that different starting diameters change the amount of space inside the 3D tent. They decorate their tents and cut doors to make a cozy home for Maisy. Finally, they record their results on a worksheet to choose the best tent.

In the real world, architects face this balance constantly. A roof must be angled to shed rain, but it must be wide enough to hold the people beneath it.

This activity takes two 45-minute sessions. Session one covers the story and the first build. Session two covers testing, iteration, decorating, and completing the worksheet. Students sit in groups of 5, but each child builds their own cones.