What is the slot, what shape, and where?
“Can a single sheet of thin paper hold a heavy pile of books across a wide gap?”
The moment: the paper bridge holding thirty heavy coins without touching the bench floor
⏱ 10:00🧰 4 materials📋 7 steps🌍 Germany Build it →Nothing matches all of that. Loosen one.
Four promises
No fire, no chemicals beyond vinegar and baking soda, no dry ice, no pressure, no mains electricity, no blades, nothing eaten. Hot water and glass only with an adult, and the page says so.
A glass bottle or a jar with a paper cone. The demonstration still works with what a school actually has.
The step where the room gasps is lit, with the seconds to say nothing and let it land. Then the why, at two levels.
A challenge comes with a ladder of hints, lightest first, and the worked solution stays hidden until you reveal it.