Science Buddies: "Ask an Expert"

Hi!

My son is working on a science fair project where he is looking to combine his love for animals with water filtration.

Specifically, he is studying the thorny devil and horned lizard and the ability of these animals to obtain water out of the ground as they walk or more effectively shovel sand onto their backs and filter the water into the mouths of the lizards by capillary action through the skin.

My son would like to test different substrates/mediums/membranes to determine which best mimics the skin of the thorny devil/horned lizard to render the most water from a sand/water combination.

We are thinking to use paper towels, coffee filters, but we need a third, preferably some form of plastic. Any ideas?

How about melamine foam aka "magic eraser" as the third option? Finding an open-cell plastic that will consolidate moisture and transport it is a bit tricky, but it seems like a magic eraser could do it (you may want to make the foam brick thinner, though): https://en.wikipedia.org/wiki/Melamine_foam -ER

Thanks!