Color Absorption
Color Absorption - Related Videos
03:02
Colors and Magnetism
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2020
Color in Coordination Complexes When atoms or molecules absorb light at the proper frequency, their electrons are excited to higher-energy orbitals. For many main group atoms and molecules, the absorbed photons are in the ultraviolet range of the electromagnetic spectrum, which cannot be detected by the human eye. For coordination compounds, the energy difference between the d orbitals often allows photons in the visible range to be absorbed and emitted, which is seen as colors by the human eye.
09:20
Color Afterimages
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2023
Source: Laboratory of Jonathan Flombaum—Johns Hopkins University Human color vision is impressive. People with normal color vision can tell apart millions of individual hues. Most amazingly, this ability is achieved with fairly simple hardware. Part of the power of human color vision comes from a clever bit of engineering in the human brain. There, color perception relies on what is known as an 'opponent system.' This means that the presence of one kind of stimulus is treated as evidence for...
10:27
Training Synesthetic Letter-color Associations by Reading in Color
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Cited by 5 •
2014
Reading in color is a new method for training letter-color associations that are typically found only in grapheme-color synesthetes. It involves an implicit form of training that has potential for long-term associative training methods because the training is a byproduct of reading and any text can be colored.
01:19
Drug Absorption: Factors Affecting GI Absorption
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2023
The process of oral drug absorption can be influenced by several factors. Weakly acidic drugs tend to be absorbed more readily from the stomach due to their nonionized state. However, absorption may be less efficient in the upper intestine, where drugs are often ionized. Interestingly, despite the stomach's apparent advantage for drug absorption, its mucous layer can hinder diffusion. Its surface area is also smaller than the intestine's, which can further slow down the absorption rate. In...
01:24
Color Vision
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2024
Color perception begins in the retina, the light-sensitive layer at the back of the eye. Two main theories explain how colors are seen: the trichromatic theory and the opponent-process theory. The trichromatic theory, proposed by Thomas Young in 1802 and extended by Hermann von Helmholtz in 1852, suggests that color vision is based on three types of cone receptors in the retina. These cones are sensitive to different but overlapping ranges of wavelengths corresponding to red, blue, and green.
FAQs
Selective absorption arises because electrons can occupy only allowed energy transitions. A photon is absorbed when its energy matches one of those transitions, linking incoming light to a particular wavelength. Different molecules, atoms, and solid materials have different electronic energy levels, so their absorption patterns can vary. This variation connects optical behavior with chemical composition.
Color absorption determines which portions of visible light remain available to reach an observer after interaction with a substance. The perceived color therefore reflects the wavelengths that are not absorbed, rather than simply the full spectrum supplied to the material. Examining this relationship helps distinguish a material's optical response from the light source itself.
Absorption patterns can reveal composition because each substance's electronic energy levels permit particular photon energies to be absorbed. A pattern therefore contains more information than a single perceived color: it reflects the set of wavelengths selected by the sample. Chemists can use that relationship in visible spectroscopy to support identification of unknown substances.
Visible spectroscopy examines which wavelengths a sample absorbs and records the resulting absorption pattern. Chemists can then compare that pattern with the substance's optical response to support identification. Because electronic transitions depend on available energy levels, the measurement connects a visible-light observation with molecular, atomic, or solid-material properties rather than treating color as an isolated visual label.
Colorimetry is especially useful when the goal is concentration rather than identification alone. The measured color-absorption behavior provides an optical basis for determining how much of a substance is present. This makes the technique relevant to chemical measurements in which a sample's composition must be quantified, while retaining the connection between the result and electronic transitions.
Color absorption can reveal changes during a chemical reaction. If the substances or electronic energy levels involved change, the wavelengths absorbed may change as well. Monitoring those optical changes gives chemists a way to follow reaction progress without relying only on the final composition, making visible measurements useful for studying dynamic chemical systems.
Pigments, dyes, and light-interacting materials are important applications because their usefulness depends on which visible wavelengths they absorb, reflect, or transmit. Studying those responses connects color absorption with molecular structure and material behavior. In chemistry, this context helps explain why different substances display different colors and why optical measurements can characterize them.