16:10, the desk by the door
Archimedes placed the centre of gravity of a hemisphere on its axis, five eighths of the radius from the pole. Stood on its round side, that point is lower than the centre of the ball, so any tilt lifts it: as the brass rocks, its centre of gravity runs along the shallow trough drawn here, which has one lowest point. Upright is that point. A minimum of potential energy is what a stable equilibrium is, and it is the kind we are named after.
Objects · Brass card stand that rights itself
Five Eighths
CHF 110 working price
For the card that says when you are back: knock the desk and it nods, then stands.
Half a ball of solid brass, round side down, with a slot across its flat face for one card. Push it over and it comes back. It has nowhere lower to go.
A study: nothing can be ordered yet. The photograph is a generated image, not a picture of a made piece or of a real person.
- Solid brass, turned and left uncoated: 58 mm across, 29 mm tall, about 430 g
- A slot 1 mm wide and 8 mm deep across the flat face holds one card upright; ten blank cards in the box
- Stands on its round side: tilt it anywhere short of its rim and it returns, and it takes its time about it
- One dot of vermilion enamel on the flat face, beside the slot: when the dot is still, it has finished
- Numbered at the pole it stands on. It also holds papers down
