Iridescence: Nature's Most Beautiful Physics Trick

Why do we see rainbows in soap bubbles? What makes an oil slick so oddly beautiful? Iridescent colors, which transform depending on the angle you look at them, are all over nature. How does physics make these shifting rainbows? We’re going to find out with the help of the National Museum of Natural History's most spectacular specimens – from bird feathers and beetle wings to fossils and gemstones.