Water lines and the lifting tower: what moves when you flushFloat ball on its arm: it falls with the water and opens the fill valveCut faces of the china, cistern and valvePressing the handle lifts the tower off its seat and about 6 litres leave the cistern in a few seconds. They pour through the rim into the bowl faster than water can trickle over the weir, so the trap runs full and becomes a siphon that pulls the bowl down to the trap mouth, where air gets in and it breaks with a gurgle. The tower floats down and seals as the cistern level falls. The float ball falls with the water, opening the fill valve, which refills the cistern and, through the small tube into the overflow, tops the bowl back up to the weir. Refilling is shown 8× faster than real time.