How to Use Physics to Escape an Ice Bowl

"I don't know who invented this crazy challenge, but the idea is to put someone in a carved-out ice bowl and see if they can get out. Check it out! The bowl is shaped like the inside of a sphere, so the higher up the sides you go, the steeper it gets. If you think an icy sidewalk is slippery, try going uphill on an icy sidewalk. What do you do when faced with a problem like this? You build a physics model, of course."

"The direct reason is that it has a thin, watery layer on the surface. But why? That liquid film exists even below the freezing point. Physicists and chemists have been arguing about this for centuries. Anyway, to start walking, there needs to be a force in the direction of motion. This is because changing motion is a type of acceleration, and Newton's second law says the net force on an object equals the product of its mass and its acceleration ( F = ma)."

A carved spherical ice bowl creates increasingly steep, slippery slopes that challenge human locomotion. Ice slipperiness arises from a thin, watery surface film that can exist below freezing, and its microscopic origin remains debated. Walking requires a forward net force because acceleration follows Newton's second law (F = ma). Forward propulsion comes from pushing backward against the ground; the ground then pushes forward via friction according to Newton's third law. Frictional force magnitude depends on contact materials and the normal force. A simplified physics model of walking on flat ground can be extended to analyze escape strategies on a slippery slope, producing animations for visualization.

Read at WIRED