Triboluminescence is the emission of light caused by mechanical stress applied to a material. This stress can be from actions like rubbing, crushing, breaking, or scratching.
- When a material is subjected to mechanical stress, it creates a separation of electric charges within the material. As the material reunites, the separated charges can recombine. This recombination releases energy in the form of a burst of visible light.
- Not fully understood: While the basic mechanism is understood, the exact process of charge separation and recombination isn’t fully established and varies depending on the material.
Examples
- Sugar crystals: When sugar crystals are crushed, they produce flashes of light due to triboluminescence.
- Adhesive tape: Quickly peeling adhesive tape in a dark environment can produce light.
- Quartz: Quartz minerals exhibit triboluminescence when they are hit or fractured.
Important Notes
- Triboluminescence is distinct from other forms of luminescence as it doesn’t rely on previous absorption of energy from light or heat.
- The intensity and colour of the light produced through triboluminescence depend on the specific material.
| Light sources | Emission mechanism | Description | Examples |
|---|---|---|---|
| LIGHT-EMITTING PROCESS | |||
| Luminescence | Light emission due to the excitation of electrons in a material. | Electrons within a material gain energy and then release light as they return to a lower energy state. | Bioelectroluminescence Electroluminescence Photoluminescence - Fluorescence - Phosphorescence Sonoluminescence Thermoluminescence |
| Blackbody radiation (Type of thermal radiation) | Electromagnetic radiation (including visible light) emitted by any object with a temperature above absolute zero. | Electromagnetic radiation (including visible light) emitted by any object with a temperature above absolute zero. | All objects above temperature of absolute zero. |
| Chemiluminescence | Light from natural and artificial chemical reactions. | Light from natural and artificial chemical reactions. | Bioluminescence Chemiluminescent reactions: - Luminol reactions - Ruthenium chemiluminescence |
| Nuclear reaction | Light emission as a byproduct of nuclear reactions (fusion or fission). | Light emitted as a byproduct of nuclear reactions. | Nuclear reactors Stars undergoing fusion |
| Thermal radiation | Light emission due to the thermal excitation of atoms and molecules at high temperatures. | Light emission due to the thermal excitation of atoms and molecules. | Sun Stars Incandescent light bulbs |
| Triboluminescence | Light emission due to mechanical stress applied to a material. | Light emission due to the mechanical stress applied to a material, causing the movement of electric charges and subsequent light emission. | Sugar crystals cracking Adhesive tape peeling Quartz crystals fracturing. |
| Natural light source | |||
| Fireflies Deep-sea creatures Glowing mushrooms | Bioluminescence | Light emission from biological organisms. | Involves the luciferase enzyme. |
| Sun Stars | Nuclear Fusion | Light emission as a byproduct of nuclear fusion reactions in stars. | Electromagnetic spectrum (visible light, infrared, ultraviolet). |
| Fire Candles | Thermal radiation | Light emission due to the thermal excitation of atoms and molecules during the combustion of a fuel source. | Burning of a fuel source, releasing heat and light. |
| Artificial light source | |||
| Fluorescent lights Highlighters Safety vests | Chemiluminescence | Light emission from chemical reactions. | Fluorescence (absorption and re-emission of light). |
| Glow sticks Emergency signs | Chemiluminescence | Light emission due to phosphorescence - a type of chemiluminescence. | A type of chemiluminescence where light emission is delayed after the initial excitation. |
| Glow sticks Light sticks | Chemiluminescence | Chemiluminescence | Light emission from a chemical reaction that does not involve combustion. |
| Tungsten light bulbs Toasters | Thermal radiation | Heated filament radiates light and heat. | Light emission from a hot filament. |
| Fluorescent lamps LED lights | Electroluminescence | Excitation of atoms by electric current. | Light emission when electric current excites atoms in a material. |
| Neon signs | Electrical Discharge | Discharge of electricity through gas. | Light emission when electricity flows through a gas. |
| Sugar crystals cracking Pressure-sensitive adhesives | Triboluminescence | Light emission from friction or pressure. | Light emission due to mechanical forces. |
| Fluorescent paint Highlighters Safety vests | Photoluminescence | Absorption and subsequent re-emission of light at a lower energy. | Absorption and re-emission of light. |
Light Sources: Mechanism, examples, and everyday applications
Footnote: Cerenkov radiation and Synchrotron radiation are not included in the table because they are not conventionally classified as light sources.
- Triboluminescence is the emission of light caused by mechanical stress applied to a material. This stress can be from actions like rubbing, crushing, breaking, or scratching.
- When a material is subjected to mechanical stress, it creates a separation of electric charges within the material. As the material reunites, the separated charges can recombine. This recombination releases energy in the form of a burst of visible light.
- Not fully understood: While the basic mechanism is understood, the exact process of charge separation and recombination isn’t fully established and varies depending on the material.