Forces Lab Educator Support
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After doing the Forces Lab, have kids do this hands-on mini-activity to get a feel for the forces at work in an arch.

Human Arch Mini-Activity

1. Have 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: Where do you feel a push or a pull? (pushing on their hands)
2. Have 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)
3. Have the group brainstorm ways for two more kids to join the arch and make it stronger, without breaking up the space beneath the arch. Guide them to the idea of adding buttresses by asking the arch-makers how stable their legs feel. Then repeat Step 2 and compare the results. (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.)