Answer: The scientific phenomenon you are referring to is called "luminescence." Luminescence is the emission of light (visible or invisible) by a substance after it has absorbed energy from an external source, such as light or other forms of electromagnetic radiation. This process results in the substance emitting light of a longer wavelength and lower energy than the absorbed radiation. Luminescence is a broad term that encompasses various subtypes of this phenomenon, including fluorescence, phosphorescence, chemiluminescence, and bioluminescence.
Here's a brief explanation of these subtypes and how they contribute to our understanding and applications across different scientific disciplines:
Fluorescence: In fluorescence, a substance absorbs energy (usually in the form of UV or visible light) and then immediately re-emits it as visible light. The emitted light ceases as soon as the excitation source (e.g., UV light) is removed. Fluorescence is widely used in biology, chemistry, and materials science for applications like fluorescence microscopy, fluorescence spectroscopy, and fluorescent labels.
Phosphorescence: Phosphorescence is similar to fluorescence but with a longer-lasting emission. After absorbing energy, a phosphorescent material can emit light for a more extended period, even after the excitation source is removed. Glow-in-the-dark materials are an example of phosphorescence. This property is useful in applications such as glow-in-the-dark products and some types of radiation dosimetry.
Chemiluminescence: Chemiluminescence involves the production of light through a chemical reaction, rather than through absorption of external energy. Common examples include glow sticks and certain types of chemical assays and detectors. This phenomenon is applied in chemistry, biochemistry, and forensic science.
Bioluminescence: Bioluminescence is the emission of light by living organisms, such as fireflies, jellyfish, and certain types of deep-sea creatures. It is a biochemical process that relies on enzymes and substrates. Bioluminescence is vital in biology for studying various organisms and their behaviors, as well as in medical and environmental research.
Luminescence, in its various forms, has a wide range of practical applications across scientific disciplines, including materials science, chemistry, physics, biology, and environmental science. It is used for detection, analysis, imaging, and as a tool for understanding the behavior and properties of substances and organisms. Additionally, luminescent materials are employed in various consumer products, safety applications, and research tools, making it a fundamental concept in science and technology.