WHY

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

With clouds, gravity pulls the water droplets out of the sky, and then they fall as rain. Here's why it rains.

We are the only creatures on Earth that cry because of our feelings. Here is the reason why we cry.

Scientists think a terrible event killed most of the dinosaurs off. But some remain—and they fly.

It could be your body's way of saying "watch out!" Here is the reason why sour things make you pucker.

It’s not actually your feet that stink. It's actually the bacteria that lives on your feet that smells.

Your movements and your feelings can give your heart a little workout. Here is why your heart beats faster sometimes.