0_Wizard
I love the color red which is at the end of the visible light spectrum. It is next to orange and opposite of violet.
Red is the colour at the end of the visible spectrum of light, next to orange and opposite violet.
chosen_Red_0
Red
chosen_topic_0_Red
Fluorescence
Fluorescence is the emission of light by a substance that has absorbed light or other electromagnetic radiation. It is a form of luminescence. In most cases, the emitted light has a longer wavelength, and therefore lower energy, than the absorbed radiation. The most striking example of fluorescence occurs when the absorbed radiation is in the ultraviolet region of the spectrum, and thus invisible to the human eye, while the emitted light is in the visible region, which gives the fluorescent substance a distinct color that can only be seen when exposed to UV light. Fluorescent materials cease to glow immediately when the radiation source stops, unlike phosphorescence, where they continue to emit light for some time after.
Grow light
A grow light or plant light is an artificial light source, generally an electric light, designed to stimulate plant growth by emitting a light appropriate for photosynthesis. Grow lights are used in applications where there is either no naturally occurring light, or where supplemental light is required. For example, in the winter months when the available hours of daylight may be insufficient for the desired plant growth, lights are used to extend the time the plants receive light. If plants do not receive enough light, they will grow long and spindly. Grow lights either attempt to provide a light spectrum similar to that of the sun, or to provide a spectrum that is more tailored to the needs of the plants being cultivated.
Color
Color (American English) or colour (Commonwealth English) is the characteristic of human visual perception described through color "categories", with names such as red, blue, yellow, green, orange, or purple. This perception of color derives from the stimulation of cone cells in the human eye by electromagnetic radiation in the spectrum of light. Color categories and physical specifications of color are associated with objects through the wavelength of the light that is reflected from them. This reflection is governed by the object's physical properties such as light absorption, emission spectra, etc.
Metamaterial cloaking
Metamaterial cloaking is the usage of metamaterials in an invisibility cloak. This is accomplished by manipulating the paths traversed by light through a novel optical material. Metamaterials direct and control the propagation and transmission of specified parts of the light spectrum and demonstrate the potential to render an object seemingly invisible. Metamaterial cloaking, based on transformation optics, describes the process of shielding something from view by controlling electromagnetic radiation. Objects in the defined location are still present, but incident waves are guided around them without being affected by the object itself.
Light-emitting diode
A light-emitting diode (LED) is a two-lead semiconductor light source. It is a p–n junction diode that emits light when activated. When a suitable voltage is applied to the leads, electrons are able to recombine with electron holes within the device, releasing energy in the form of photons. This effect is called electroluminescence, and the color of the light (corresponding to the energy of the photon) is determined by the energy band gap of the semiconductor. LEDs are typically small (less than 1 mm) and integrated optical components may be used to shape the radiation pattern. Appearing as practical electronic components in 1962, the earliest LEDs emitted low-intensity infrared light.
Infrared photography
In infrared photography, the film or image sensor used is sensitive to infrared light. The part of the spectrum used is referred to as near-infrared to distinguish it from far-infrared, which is the domain of thermal imaging. Wavelengths used for photography range from about 700 nm to about 900 nm. Film is usually sensitive to visible light too, so an infrared-passing filter is used; this lets infrared (IR) light pass through to the camera, but blocks all or most of the visible light spectrum (the filter thus looks black or deep red). ("Infrared filter" may refer either to this type of filter or to one that blocks infrared but passes other wavelengths.)
Ultraviolet
Ultraviolet (UV) is an electromagnetic radiation with a wavelength from 10 nm to 400 nm, shorter than that of visible light but longer than X-rays. UV radiation constitutes about 10% of the total light output of the Sun, and is thus present in sunlight. It is also produced by electric arcs and specialized lights, such as mercury-vapor lamps, tanning lamps, and black lights. Although it's not considered an ionizing radiation because its photons lack the energy to ionize atoms, long-wavelength ultraviolet radiation can cause chemical reactions and causes many substances to glow or fluoresce. Consequently, the chemical and biological effects of UV are greater than simple heating effects, and many practical applications of UV radiation derive from its interactions with organic molecules.
1_Apprentice
It is a very symbolic color, for sure!
0_Wizard
Yes! The Mayans and Ancient Egyptians colored their faces red for ceremonies. Roman generals also colored their bodies red to celebrate if they had a victory.
The Ancient Egytians and Mayans coloured their faces red in ceremonies; Roman generals had their bodies colored red to celebrate victories.
chosen_Red_0
Red
chosen_topic_0_Red
Red
Red is the colour at the end of the visible spectrum of light, next to orange and opposite violet. It has a dominant wavelength of approximately 625–740 nanometres. It is a primary color in the RGB color model and the CMYK color model, and is the complementary color of cyan. Reds range from the brilliant yellow-tinged scarlet and vermillion to bluish-red crimson, and vary in shade from the pale red pink to the dark red burgundy. The red sky at sunset results from Rayleigh scattering, while the red color of the Grand Canyon and other geological features is caused by hematite or red ochre, both forms of iron oxide.
Ancient Egypt
Ancient Egypt was a civilization of ancient Northeastern Africa, concentrated along the lower reaches of the Nile River in the place that is now the country Egypt. It is one of six historic civilizations to arise independently. Egyptian civilization followed prehistoric Egypt and coalesced around 3100 BC (according to conventional Egyptian chronology) with the political unification of Upper and Lower Egypt under Menes (often identified with Narmer). The history of ancient Egypt occurred as a series of stable kingdoms, separated by periods of relative instability known as Intermediate Periods: the Old Kingdom of the Early Bronze Age, the Middle Kingdom of the Middle Bronze Age and the New Kingdom of the Late Bronze Age.
Ancient Egyptian race controversy
The question of the race of ancient Egyptians was raised historically as a product of the early racial concepts of the 18th and 19th centuries, and was linked to models of racial hierarchy primarily based on craniometry, anthropometry and genetics. A variety of views circulated about the racial identity of the Egyptians and the source of their culture. These were typically identified in terms of a distinction between the Caucasoid and Negroid racial categories. Some scholars argued that ancient Egyptian culture was influenced by other Afroasiatic-speaking populations in Northeast Africa, the Maghreb, or the Middle East, while others pointed to influences from various Nubian groups or populations in Europe.
Egyptians
Egyptians (  ; ""; ; "Ni/rem/en/kīmi") are an ethnic group native to Egypt and the citizens of that country sharing a common culture and a common dialect known as Egyptian Arabic. Egyptian identity is closely tied to geography. The population of Egypt is concentrated in the lower Nile Valley, the small strip of cultivable land stretching from the First Cataract to the Mediterranean and enclosed by desert both to the east and to the west. This unique geography has been the basis of the development of Egyptian society since antiquity. The daily language of the Egyptians is the local variety of Arabic, known as Egyptian Arabic or "Masri.
Black Egyptian hypothesis
The Black Egyptian hypothesis is the hypothesis that ancient Egypt was a predominantly Black civilization, as the term is currently understood in modern American ethnic perception. Mainstream scholars recognize that many indigenous Egyptians (e.g. Nubians), including several Pharaohs, were of ancestry that, in the modern era, would be considered "black". The Black Egyptian hypothesis goes much further, claiming that Egypt, from north to south, was a black civilization. It includes a particular focus on identifying links to Sub-Saharan cultures and the questioning of the race of specific notable individuals from Dynastic times, including Tutankhamun, the king represented in the Great Sphinx of Giza, and Cleopatra.
Ancient Egyptian technology
Ancient Egyptian technology describes devices and technologies invented or used in Ancient Egypt. The Egyptians invented and used many simple machines, such as the ramp and the lever, to aid construction processes. They used rope trusses to stiffen the beam of ships. Egyptian paper, made from papyrus, and pottery were mass-produced and exported throughout the Mediterranean basin. The wheel was used for a number of purposes, but chariots only came into use after the Second Intermediate period. The Egyptians also played an important role in developing Mediterranean maritime technology including ships and lighthouses.
Population history of Egypt
Egypt has a long and involved demographic history. This is partly due to the territory's geographical location at the crossroads of several major cultural areas: Northeast Africa, the Maghreb, the Sahara, Sub-Saharan Africa, the Middle East, and the Mediterranean. In addition, Egypt has experienced several invasions during its long history, including by the Canaanites, the Ancient Libyans, the Assyrians, the Kushites (a Nubian civilization), the Persians, the Greeks, the Romans, and the Arabs. During the Paleolithic period, the Nile Valley was inhabited by various hunter-gatherer populations. Around 8000 BCE, the Sahara had a wet phase, the Neolithic Subpluvial (Holocene Wet Phase).
1_Apprentice
That makes sense! It is the color of blood after all. I think purple had a lot of symbolism back then too didn't it?