#37: The Self-Cleaning Doorknob
This next fact sounded so crazy that I had to look it up myself. How in the world would a doorknob sanitize itself? Does it have tiny little arms that come out at night to wipe itself down with antibacterial wipes? But it turns out that it’s true!

It works through something called the oligodynamic effect, which is where the ions on metal get absorbed by bacteria and then destroy them. So it’s actually true that a metal doorknob can kill bacteria that are lurking on it. It’s crazy to think that people were using metal doorknobs long before this effect was discovered. It’s just an accidental benefit!