Module 1   Qanuq Ilitaavut (Way of Knowing) Human Tent Arch
Arch A curved structure that converts the downward compression force of its own weight, and of any weight pressing down on top of it, into a force along its curve. This results in an outward and downward force along the sides and base of the arch.
Buttress A side support that counteracts an outward pushing force, the way bookends keep books on a shelf from sliding sideways. Buttresses are often used to support the sides of arches and tall cathedral walls, where they counteract the outward thrust.
1. Pair your students in teams of four.
2. Two kids form an arch by placing their palms together and leaning toward each other, sliding their feet as far back as they can. Caution them not to lose their balance.
Ask students: Where do you feel a push or a pull? (pushing on their hands) 3. A third kid gently pull down on the top of the arch to test its strength. Ask: How difficult is it to break the arch? (not difficult)
4. Ask: Do you have any ideas to how we can make the arch stronger without breaking up the space beneath the arch?
Let students converse in their teams for some possible answers. Guide students to the idea of adding buttresses by asking the arch-makers how stable their legs feel.
5. Repeat step 2, but this time the two remaining students sit with their backs against the feet of the two students forming the arch.
How strong is the arch now?
The buttresses exert an inward force on the sides of the arch that balances the outward force created by the load pressing down on the top of the arch.