I found some cool science on Youtube a few days ago that I wanted to share. In this video, heated carbon nanotube wires use the "mirage" effect to help hide an object in water. In this effect, the rapid heating of the wire (caused by the resistance to the large amount of current passing through it) causes a change in the index of refraction of the water, which bends the light passing through it. All in all, it's a pretty cool video.
Image via Wikipedia
