And the other idea =D

How many pin holes, on a piece of paper covering the opening of a cup, does it take for water from an inverted cup, full of water, to leak through the holes in the paper?

This is the experiment investigating bonds formed between water molecules, and the basics to how an umbrella works ^.~.

The independent variable is the number of pin holes I poke into the paper.
The dependent variable is whether the water will leak through the holes or not.
Controlled variables:

• same cup used for repetition of experiment
• paper has to be pressed firmly down along the edge of the cup, so it creases along the edge of the cup.
• paper has to be flat.
• use the same pin every time for poking the holes
• use paper of the same thickness
• don't squeeze water out of cup, so hold it in the same way for each repetition of the experiment

I don't know which experiment to choose...