At the nanoscale, all properties change including optical
properties. The phenomenon was first observed by Isaac Newton (the discoverer
of the gravity theory) and Robert Hooke (the inventor of the microscope and
telescope) and was described by Thomas Young in details a century later as wave
interference - at certain angle light waves can interfere constructively (light
reflected from both surfaces) or substracted (light cancelled out from both
surfaces).
When visible light strucks the fine nano-structure or
topography of pigmented parts on butterfly wings, peacock tail feathers and duck
neck feathers and even soap bubbles; the wings, feathers or soap bubbles will
turn iridescent - green, blue and turquoise beautifully blended according to
the electromagnetic spectrum. Apart from interference ability, duck feather is
also hydrophobic (water-repellent) which keeps air trap within its feather and
increases its buoyancy.
Other nano-scale effects are wave-particle duality, higher surface to volume ratio, higher reactivity, Brownian motion, electromagnetic forces (at atomic scale) and weak and strong nuclear forces (anything greater than 10-4 nm) while gravitation force is negligible. Nano-scale effects are pretty much everything that is related to Quantum Physics.
From nature, many bio-mimetic materials could be used for industry and commercial purposes such as anti-reflective window glass (by using array of pillars that are smaller than wavelength of light), optical-switches and military camouflage.
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Ducks at Kew Royal Botanic Gardens, London
Ducks at Hyde Park, a Royal Park, London
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