Bathroom Readers Institute - Do Geese Get Goose Bumps?: & More Than 199 Perplexing Questions with Astounding Answers

Q: How do cords get tangled?

A: You pull off your ear buds and absentmindedly toss them into your pocket. The next time you reach for them, the cord has somehow become tangled, knotted, and bunched up several times over. How could this happen? There wasnt even anything else in there! This mysterious affliction also affects extension cords, Christmas lights, curtain strings, and more. The culprits: cord gremlins. These nasty little beasties sneak in when youre not around and laugh maniacally as they mangle your cord into a tangled headache.

And if you dont buy that explanation, theres actually a scientific discipline devoted solely to understanding this exact conundrum. Its called knot theory. Proponents of this (admittedly small) discipline have used complex mathematic formulas to prove that there is almost a 100 percent chance that something that can knot in storage will knot in storage. Thats because, even though there is only one way for a cord to be untangled, there are hundreds of ways for it to get tangled in the first place. There are countless types and styles of knots, and they can combine with each other in any way you can imagineand in some ways you cant.

Any place on the cord at which it can bend is called a contact point. The more contact points on a cord, the more possibilities there are for the cord to bend and thus knot itself. Pliable cords for headphones and Christmas lights have so many contact points that tiny changes in the environmenteven temperature variationscan cause those contact points to bend, move, and wrap around each other. Lets say those ear buds are in your coat pocket and you placed the coat gently over a chair. That little bit of motion is enough to make the cord bend in at least one place, but probably more. Then you pick up the coat (more bending), put it on (more bending), and start walking toward the door (more bending). By the time you get to get the ear buds out of your pocket, the cord is all knotted up.

The only way to keep this from happening: properly wrap or store your cord in such a way that it cant tangle. When it comes to headphone cords, wrapping them around a small piece of cardboard should keep them safe from the cord gremlins.

Q: How does soap work?

A: Just combine it with warm or hot water, and soap always seems to know just how to get rid of the grime you dont want on your skin (or your clothes, dishes, bathroom sink, etc.), and not remove anything else but the grime. The underlying scientific principle is quite simple, and its a variant of the old adage oil and water dont mix. Its true: oil and water really dont mix, so when you wash your hands with soap and water, the soap breaks down the impurities on your hands (which consist partially of naturally occurring oils, along with other stuff) into smaller molecules. Soap is made from ingredients that are hydrophilic at one end and hydrophobic at the other, which means they are attracted to and repel water, respectively.

As the tap wateralong with the water present in the soap itselfbreaks down dirt and oils into smaller molecules, the hydrophobic molecules in the soap attach themselves to those increasingly smaller dirt and oil bits. This creates a new kind of oil droplet, one thats smaller than a water molecule. And because of the hydrophilic soap molecules, this droplet is attracted to that water. The dirt becomes absorbed inside of the water moleculewhich washes right off your hands and then goes down the drain.

Q: Why do coffee stains leave a ring?

A: If youve never noticed it before, you will the next time you see a dried coffee stain on a table or a counterthe outside of the stain has become a dark brown border, while the inside of the stain is almost completely gone. Whats going on? Its actually quite fascinating.

When the coffee, which is made up of water and coffee grounds, spills onto a flat surface, it starts spreading out in every direction. The flow stops when it hits something, usually a tiny crack or crevice that you cant even see. Thats why spilled coffee is shaped like a haphazard splotch instead of a perfect circle (because truly flat surfaces are very rare).

Once the coffee stain settles, the water starts evaporating. That occurs on the outer edges first, because the puddle is the thinnest there. Along with evaporation comes replenishment. The coffee is pulled from the center out to the edges to replenish the evaporated bits, and the tiny coffee grounds are pulled all the way to the edges of the splotch and then collect in the tiny crevices that shaped the stain. After the water is gone, all thats left of the spill has collected along the dark brown edges.