WHY

What causes a runny nose? Spicy foods, cold weather, and—strangely—crying. Here’s why.

It is possible for urine to be different colors. But yellow pee is a sign that your body is healthy.

As we get older, we lose some of the stuff in our skin that helps it to stretch and then return to its normal place.

Do you know the saying “what goes up, must come down”? Here is why we don't fall off the Earth.

Chemicals from special glands on a dog's rear end tell other dogs a lot about them. Here's why dogs sniff each other's butts.

Parrots can learn how to say hundreds of words—and even know what some of them mean.

It all comes down to vocal cords and hormones. Here's why girls' voices are usually higher than boys' voices.