The Pythagorean Siphon Inside Your Washing Machine

Summary by Krater

Steve Mould explains the physics of the pythagorean cup, demonstrating how a concealed siphon allows liquid to empty from a compartment only when a critical fluid level is reached, and compares this mechanism to washing machine drawers and toilet siphons.

From the video

Answers: How does a pythagorean cup or toilet siphon mechanism work?

• Pythagorean cup mechanics
• Fluid siphoning physics
• Washing machine fabric softener tray
• Toilet cistern siphon mechanism

What it concludes

• A pythagorean cup relies on a concealed siphon that is triggered when liquid reaches a critical top opening.
• Surface tension creates a seal at the top of the siphon tube, allowing the weight of the water in the central chamber to pull the remaining liquid out.
• Washing machine fabric softener trays and certain toilet flush systems use this same greedy cup siphon mechanism to empty completely.
• If a toilet supply is too leaky and the water level merely dribbles over the siphon top rather than priming it, the siphon fails to start.