Water suspension(atmospheric pressure/surface tension)

Works via a cup with holes drilled on the bottom and a piece of tape acting as a simple valve on the top. If the tape is peeled back water/air can flow, otherwise if kept level the water will happily sit there.

Partially based on thread here a few weeks ago, wanted to prove to myself that this concept would work in reality(beyond a simple straw or pipette).

Have some thoughts that it might work for novelty applications(fish tanks, water spheres). A somewhat practical, bottom filling bucket could also be done, but haven't figured out a good valve design to minimize manual operation. Goes without saying applications would need to work around the obvious issue, but nothing strictly impossible to deal with. Water locks, pumps, etc.

Left: Water filled, Tape in place

Right: Rapidly draining, Tape peeled back

Below: Simple model of what a clean version might look like.