These wings from a Morpho butterfly are normally bright blue thanks to structural color. Because the nanosized spacing between the wings’ scales (micrograph) matches blue light’s wavelength (between 400 and 500 nm), when white light hits the wings, this iridescent blue is amplified while other colors are tamped down. However, when YouTuber Tommy Technetium gets the wings wet and the liquid fills those small gaps between the scales, the liquid warps the light’s wavelengths such that 400–500 nm wavelengths correspond to a greener color, which is what we see when liquid nitrogen is poured onto the wings (above).
Other liquids create different colors, like the isopropyl alcohol solution in the video below and the other liquids in the multipanel image. Those other liquids are as follows: (a) air; (b) n-hexane; (c) ethanol; (d) water; (e) 400:1 methanol/Triton X solution before methanol evaporation; (f) Triton X-treated wing after methanol evaporation; (g) Triton X-treated wing with water; (h) Triton X-treated wing with saturated sugar water; (i) Triton X-treated wing gently rinsed and wet with water; (j) acetone; (k) toluene; (l) water.
Do science. Take pictures. Win money. Enter our photo contest here.