Yes, highlighters glow under UV light, often called blacklight.
Why Do Highlighters Glow Under UV Light?
Highlighters are designed with fluorescent ink, which is key to their vibrant appearance and ability to glow. Fluorescence is a fascinating phenomenon where a substance absorbs light at one wavelength and emits it at another, typically longer, wavelength.
The Science Behind the Glow
- Absorption of UV Light: Highlighter ink contains compounds that absorb ultraviolet (UV) light. UV light is a form of electromagnetic radiation invisible to the human eye.
- Emission of Visible Light: When these compounds absorb UV light, they get excited and jump to a higher energy level. To return to their normal, stable state, they release the extra energy as visible light. This process is what makes the highlighter marks glow brightly under a blacklight.
The Role of Blacklight
A blacklight is a type of lamp that emits long-wave ultraviolet (UV-A) light and very little visible light. It's commonly used to observe fluorescence since many substances fluoresce when exposed to UV light.
- Normal Blacklight: The typical blacklight used in various settings, including parties and scientific experiments, emits UV-A light, which is perfect for making fluorescent substances glow.
Practical Applications
The ability of highlighters to glow under UV light is not just a fun trick; it has practical uses, too.
- Security: Some security features use fluorescent inks that are invisible under normal light but glow under UV light, helping to verify the authenticity of documents and currency.
- Art and Entertainment: Artists use fluorescent paints and inks to create stunning visual effects in paintings, murals, and stage productions that come alive under blacklight.
- Scientific Research: In scientific research, fluorescent markers are used to label and track biological samples, such as proteins and DNA, under a microscope.
Examples of Fluorescent Materials
Many everyday items contain fluorescent materials that glow under UV light.
| Item | Description |
|---|---|
| Tonic Water | Contains quinine, which glows bright blue under UV light. |
| Laundry Detergents | Often contain optical brighteners that make clothes appear whiter by fluorescing under UV light. |
| Teeth and Nails | Naturally contain fluorescent compounds that make them glow slightly under UV light. |
| Some Minerals | Certain minerals, like fluorite and calcite, fluoresce in various colors under UV light. |
| Antifreeze | Many types of antifreeze contain fluorescent dyes, which can glow under UV light. |
| Vitamins | Certain vitamins, particularly vitamin A and some B vitamins, exhibit fluorescence under ultraviolet light. |
| White Paper | Most white paper contains fluorescent compounds to enhance its brightness and whiteness. |
| Body Fluids | Some body fluids, such as urine, can exhibit fluorescence due to the presence of certain compounds. |
| Petroleum Jelly | Petroleum jelly can glow under a black light. |
| Honey | Honey can also glow under a black light. |
| White Fabric | Certain white fabrics, especially those treated with optical brighteners, can fluoresce under UV light. |
| Ripe Bananas | Ripe bananas can exhibit a blue glow under UV light due to the presence of fluorescent compounds. |
| Flowers | Certain flowers, such as daisies, can display vibrant colors under UV light that are not visible in natural light. |
| Some Scorpions | Some scorpions fluoresce under UV light. |
| Some Cleaning Agents | Some cleaning products contain fluorescent dyes that glow under UV light. |
| Certain Plastics | Some plastics are manufactured with fluorescent additives that make them glow under UV light. |
Highlighters are designed to be noticed, and their ability to glow under UV light is a testament to the clever use of fluorescence. Highlighters fluoresce under a normal blacklight because the ink absorbs ultraviolet light, which is not visible to the human eye, and remits it as visible light.
