Well Antz4fun, it's not necessarily a problem I think CoolColJ is trying to solve, he's just trying to brainstorm and invent something that may benefit everyone here. Out of 100 ideas, 99 fail but 1 improves the world by a slight margin. Or something like that. The world's first computer was considered a hobbyist's item at first. Although your point is valid, playing devil's advocate and entertaining new ideas without accepting them can be fun at times.
While we are at it, I would challenge the idea of using a cotton ball as a medium to convert a potentially lethal body of water into something less dangerous for ants. We are trying to find a material, or combination of materials, that can perform the following:
1. Retain and block off a body of water,
2. Either retain water within itself or allow moisture to pass through itself (breathable) without violating rule #1,
3. Able to be penetrated without losing the ability to perform rules #1 & 2, with or without the assistance of other materials.
4. Be small or able to be cut down into a size and shape to fit a general use test tube for its intended use.
I think we have cotton balls, meshes, sponges, washers ("rings"), and glues/adhesives/putties so far. I would add in garden fabric (permeable barrier) and cotton/polyester fabrics. Also, we can take advantage of the fact that surface tension holds water molecules together so tiny holes in any materials in direct contact with the water reservoir do not interfere with rule #1. Hopefully these 4 rules may generate more ideas. Additions/revisions are always welcome.