Where do colours come from Grzegorz Karwasz Andrzej

Where do colours come from? Grzegorz Karwasz Andrzej Karbowski Ania Kamińska* Krzysztof Służewski Didactics of Physics Division, Institute of Physics Faculty of Physics, Astronomy and Applied Informatics, Nicolaus Copernicus University in Toruń * Pomeranian Pedagogical University, Słupsk, Poland dydaktyka. fizyka. umk. pl

What colour is the pink lamp?

What colour is the blond hair?

What are the colours of a soap ball?

What are the colours of a rainbow? Ultra. Violet Infra. Red ? http: //dydaktyka. fizyka. umk. pl/Wystawy_archiwum/z_omegi/tecza. html (foto S. Lorenzo in Banale, GK, 19. 09. 2014) Tęcza na suficie Ultra. Violet Infra. Red

• Physics • Chemistry • Biology • Psychology = Intersdisciplinary pathways [please copy] Visible ligth: 380 nm – 760 nm 1. 65 e. V – 3. 3 e. V

What colours is the blond hair?

What colour is the pink lamp? Diffraction gratings:

Two more pink lamps

The same? helium nitrogen (N 2)

How do we measure colours? 2 lampy

USA filters What are the basic colours? In emission (i. e. addition): red, green, blue In print (i. e. subtraction): cyan, magenta, yellow TV set in one of Paris hotels (2004) Window in one Berlin shop (2005)

What are the basic colours? Red: ~ 600 -700 nm Green: 495 -570 nm Magenta: 380 – 500 + > 600 nm teachersource. com (USA)

Physics: diffraction Δl=nλ Energy saving lamp Colours from diffraction on a CD Sunrise

Where do colours come from? Physics Refraction, i. e. different velocity of propagration for different wavelengths: n =1. 4 for red, n= 1. 45 for violet

Where do colours come from? Physics Morpho Menelaus: male vs female Colours from diffraction on gratings of the wing

Why the sky is blue? Separation of colours by selective diffusion (scattering)

More, complementary sky colours Foto: Carmen Busco, Sao Paolo With kind thanks!

Atmospheric spectroscopy Isola di Rodi, Foto Federico Fedrizzi Rayleigh scattering Berlin, 22. 06. 2005, photo GK

Where do colours come from? River Separation of colours by selective reflection/ absorption in water (blue is transmitted into water, red is reflected)

Where do colours come from? – Sunglasses Colours from selective reflection Colours from absorption

Swarovski’s piramide (and sphere) Brown, deep blue, yelowish - these are not basic colours: refraction in the piramide + selective reflection from bottom layer.

What colours are soap bubbles? Basic colours in absorption (in print): magenta, cyan, yellow= double colours in emission: magenta=blue + red, etc. .

Colours of soap bubbles Constructive interference of reflected ligth: http: //www. amazingbubbleman. com/shared-links/ .

What are the colours of rainbow? Infra. Red n=1, 343 Blue comes from a lower angle http: //dydaktyka. fizyka. umk. pl/Wystawy_archiwum/z_omegi/tecza. html (foto S. Lorenzo in Banale, GK, 19. 09. 2014) Tęcza na suficie Ultra. Violet n=1, 332

What are the colours of (a) rainbow? Infra. Red http: //dydaktyka. fizyka. umk. pl/Wystawy_archiwum/z_omegi/tecza. html (foto S. Lorenzo in Banale, GK, 19. 09. 2014) Tęcza na suficie Ultra. Violet

Magenta? What are the colours of rainbow? http: //dydaktyka. fizyka. umk. pl/Wystawy_archiwum/z_omegi/tecza. html (foto S. Lorenzo in Banale, GK, 19. 09. 2014)

What are the colours of rainbow? Several diffraction series, depending on droplets’ sizes

Where do colours come from? Chemistry The emission spectrum of hydrogen (a) and helium (b) Chemistry, i. e. electrons with energies according to Bohr, Schrödinger and Pauli

Where do colours come from? Chemistry + Physics Atoms in crystaline electrostatic field: a) quartz: Si. O 2 b) amethyst: Fe+2 in Si. O 2 c) azurite: Cu. SO 4 Saphire: Fe+2 in Al 2 O 3

Physics: non-isolated atoms Atoms in crystaline electrostatic field – energy levels get shifted: a) Cr+3 (yellow) gets greenish in glass b) Cr+3 in Al 2 O 3 gets red-like (= ruby) G. Karwasz, Rubiny i berlińskie szkło, Chemia w Szkole 3/2012

Where do colours come from? Organic chemistry 330 px-Indigofera_tinctoria 1 Absorbs yellow-to-red (=orange), so it appears blue (i. e. indigo) Usually extra electrons on double bonds

Organic chemistry: Cochenille red [czerwiec] Absorbs violet-to-yellow, so it appears carmine-red A. Withney et al, Applied Spectroscopy 61 (2007) 994

Tonic water: absorption and emission bands are shifted http: //chemwiki. ucdavis. edu/Core/Analytical_Chemistry/ Analytical_Chemistry_2. 0/10_Spectroscopic_Methods/10 F%3 A_Photoluminescence_Spectroscopy http: //www. olympusmicro. com/primer/techniques/confocal/fluoroexciteemit. html

Jabłoński diagram e. g. chlorophyll Fluorescence („immediately”) Phosphorescence (delayed)

Why chlorophyll is green? absorption and emission spectra of chlorophyll

Chlorophyll does not absorb green! chlorophyll solution illuminated lasers: (b) violet, (c) green and (d) red (a) is the chlorophyll solution seen in white ligth and (e) is water in red ligth M. Gagoś, G. Karwasz, Chemia w Szkole (2012)

And what in theew in this bottle? absorption and fluorescence spectra of 7 -hydroxycoumarin Probably nothing for kids simplified Jablonski diagram

Colours of cabbage

Pelargonia, kompot z wiśni, zasada Changing p. H↔changing equilibrium Flavonoids, caretonoids, etc. M. Gagoś, G. Karwasz, Colour and chemical Structure, Chemia w Szkole 3/2012

Absorption curves 2 intersections: 3 different forms

The role of the solvent: shifiting levels 4 - dimethylamino-4’nitrostilbene

Proszę wyjąć komórki How can we see infrared? Infrared sensors of vipers photo GK i https: //it. wikipedia. org/wiki/Crotalus

Why there is no blue flowers (inpollinated by bees)? Baptisia austrialis (false indigo) CC BY-SA 3. 0, https: //commons. wikimedia. org/w/index. php? curid=173802 http: //galeria. swiatkwiatow. pl/zdjecie/chaber-blawatek, 110360, 721. html Centaurea cyanus (cornflower)

Bees see violet, but not blue! Bees’ eye is different from human. Bees eye is best to see solid colors, especially yellow, but sees also ultraviolet (maximum sensitivity of 344 nm). Bees can see the contrast of green and brown for them is black. G. Karwasz, On the Track of Modern Physics, UMK

Colors, the eye of the bee Cherry flowers in UV

Butterfly impressionst 15 different colour receptors (other butterflies only 4, including UV) http: //www. sciencemag. org/news/2016/03/butterfly-has-extreme-color-vision? utm_campaign=email-news-latest&et_rid=35353469&et_cid=327254

Colors, the eye of artists Claude Monet, Ponte d’Argenteuil

Colors, the eye of artists: no automatic white adjustment Cathédrale de Rouen

Where do colours come from? Arts Nature 402, 855 - 856 (23/12/1999); Visual Perception: Reflections on colour constancy KARL R. GEGENFURTNER Claude Monet, Gare Saint Lazare, (1877), Orsay, Photo GK Paul Signac, Le château de Papes (1900), Orsay, Photo GK

• This butterfly has extreme color vision • By Virginia Morell Mar. 8, 2016 , 4: 00 PM • Butterflies may not have a human’s sharp vision, but their eyes beat us in other ways. Their visual fields are larger, they’re better at perceiving fast-moving objects, and they can distinguish ultraviolet and polarized light. Now, it turns out that one species of swallowtail butterfly from Australasia, the common bluebottle (Graphium sarpedon, pictured), known for its conspicuous blue-green markings, is even better equipped for such visual tasks. Each of their eyes, scientists report in Frontiers in Ecology and Evolution, contains at least 15 different types of photoreceptors, the light-detecting cells required for color vision. These are comparable to the rods and cones found in our eyes. To understand how the spectrally complex retinas of butterflies evolved, the researchers used physiological, anatomical, and molecular experiments to examine the eyes of 200 male bluebottles collected in Japan. (Only males were used because the scientists failed to catch a sufficient number of females. ) They found that different colors stimulate each class of receptor. For instance, UV light stimulates one, while slightly different blue lights set off three others; and green lights trigger four more. Most insect species have only three classes of photoreceptors. Even humans have only three cones, yet we still see millions of colors. Butterflies need only four receptor classes for color vision, including spectra in the UV region. So why did this species evolve 11 more? The scientists suspect that some of the receptors must be tuned to perceive specific things of great ecological importance to these iridescent butterflies—such as sex. For instance, with eyes alert to the slightest variation in the blue-green spectrum, male bluebottles can spot and chase their rivals, even when they’re flying against a blue sky. • • www. sciencemag. org

Butterfly impressionist 15 different colour receptors http: //www. sciencemag. org/news/2016/03/butterfly-has-extreme-color-vision? utm_campaign=email-news-latest&et_rid=35353469&et_cid=327254

Butterfly with extreme color vision • This butterfly has extreme color vision • By Virginia Morell Mar. 8, 2016 , 4: 00 PM • Butterflies may not have a human’s sharp vision, but their eyes beat us in other ways. Their visual fields are larger, they’re better at perceiving fast-moving objects, and they can distinguish ultraviolet and polarized light. Now, it turns out that one species of swallowtail butterfly from Australasia, the common bluebottle (Graphium sarpedon, pictured), known for its conspicuous blue-green markings, is even better equipped for such visual tasks. Each of their eyes, scientists report in Frontiers in Ecology and Evolution, contains at least 15 different types of photoreceptors, the light-detecting cells required for color vision. These are comparable to the rods and cones found in our eyes. To understand how the spectrally complex retinas of butterflies evolved, the researchers used physiological, anatomical, and molecular experiments to examine the eyes of 200 male bluebottles collected in Japan. (Only males were used because the scientists failed to catch a sufficient number of females. ) They found that different colors stimulate each class of receptor. For instance, UV light stimulates one, while slightly different blue lights set off three others; and green lights trigger four more. Most insect species have only three classes of photoreceptors. Even humans have only three cones, yet we still see millions of colors. Butterflies need only four receptor classes for color vision, including spectra in the UV region. So why did this species evolve 11 more? The scientists suspect that some of the receptors must be tuned to perceive specific things of great ecological importance to these iridescent butterflies—such as sex. For instance, with eyes alert to the slightest variation in the blue-green spectrum, male bluebottles can spot and chase their rivals, even when they’re flying against a blue sky. • • www. sciencemag. org

Conclusions (human eye) • Human eye, differently from ear, performs only limited harmonic analysis (but frequencies are extremely high – 1018 Hz) • In this way, violet and magenta are different but yellow and green-red seem the same • Additionally, normal eye performs automatic white-balance correction • Impressionists probably were free from this automatic mechanism

Conclusions (physics) • Few physical mechanisms can be defined forming colours: - refraction, best visible in prism (and not so well in rainbow) - diffraction, best visible in grating, like CD and Morpho wing - separation by different absorption, like in sunset and under water - interference, like in soap bubble (and in under- rainbow)

Conclusions (chemistry) • All other ways of forming colours are to be attributed to chemistry (so-called electronic spectra): - emission (and absorption) from gas phase – like in „economic” ligth bulbs, laboratory hydrogen tubes, neons, sodium street lamps and fluorescent tubes - emission (and absorption) from atoms isolated in glass or crystalline matrix – sapphires (Fe in Ti. O 2), rubids (Cr in Ti. O 2), ametysts (Fe in Si. O 2) - absorption of so-called dyes – complex molecules with superimposed electronic absroption and emission lines (usually shifted, due to Jabłoński diagram) - delayed emission (phosphorescence) - dyes „harvest” in wide field of the spectrum (including UV) and emmit in specific regions of visible (also UV and i. R)

Conclusions (biology) • - Evolution „provided” different species with specific detectors: Humans with red-yellow, yellow-green, blue-violet rodopsina Bees with violet (and UV) pigments Vipers with IR sensors Butterfiles (with small brain) with numerous (up to 14) seperate-range dyes Aditionally, bees recognise polarization of ligth Detection of polarized ligth allows octopusy to hunt jellyfish Chamaleonts skin contains orientable diffraction-like crystals (guanine) that reflect at adjustable wavelegth (blue or white), yellow and gree pigments and bottom layer of melanina Multi-facets eyes of insects mimic complex elaboration of the picture that human brain performs Best in colour detection and elaboration are impressionists Thanks for the audience (and vision)