[legierski]

Check out aLOKSAK bags. I've successfully tested my Nexus 7 tablet under the shower with one of these bags. For scientific purposes, of course.

[enscr]

For science, I'd put silica gel crystals in it and take it to the shower before I dunk my tablet :)

[deegles]

You could just use a square of cardboard... why use electronics at all :)

[enscr]

Because it won't tell you if there's humidity inside the bag that could potentially harm your device. Silica gel isn't electronics. It'll change color when it detects moisture.