Pythagorean cup

When it is filled beyond a certain point, a siphoning effect causes the cup to drain its entire contents through the base.

[1] When the cup is filled, liquid rises through the second pipe up to the chamber at the top of the central column, following Pascal's principle of communicating vessels.

Gravity then creates a siphon through the central column, causing the entire content of the cup to be emptied through the hole at the bottom of the stem.

Once the liquid reaches the top of the Pythagorean siphon it begins to escape through the central chamber as the effects of gravity take hold.

The weight of the fabric softener diluted with water has no access to the outside air because of the seal which then causes all the mixture to be poured directly into the washing machine.