Many people, from children to the elderly, wear glasses. Andy, age 5, wants to know how they work.
Whether we're happy or sad, it doesn't take much to turn on the waterworks. But how and why do humans cry?
They're more than windows into the soul – they're a portal into our possible future.
We're used to thinking of our eyes detecting light as the foundation of our visual system. But what's going on in other cells throughout the body that can detect light, too?