Fluorescence is the phenomenon of luminescence caused by light. When a certain normal temperature substance is irradiated by incident light (usually ultraviolet or X-ray) of a certain wavelength, it will enter an excited state after absorbing the light energy, immediately de-excited and emit outgoing light (usually light with a longer wavelength). Greater than the wavelength of the incident light, in the visible light band); once the incident light stops, the fluorescence will disappear immediately. The emitted light with this characteristic is called fluorescence.

Is highlighter the same as light stick?

The fluorescence of highlighter is different from the fluorescence principle of light sticks that people use at parties. The chemical substances in the light stick are mainly composed of three substances: peroxides, ester compounds and fluorescent dyes. Simply put, the principle of the glow of the fluorescent stick is that peroxide reacts with ester compounds, and the energy after the reaction is transferred to the fluorescent dye, and then the dye emits fluorescence. This process realizes the conversion of chemical energy to light energy. Therefore, they can emit light at night without any ultraviolet light. Highlighter needs to be exposed to ultraviolet light to emit fluorescence.

In fact, there is a kind of fluorescence phenomenon in nature. On summer nights, we will see fireflies flying. These fluorescence are caused by the chemical reaction of the light-emitting cells of the firefly to produce the fluorescence that is visible to the naked eye, that is, the fluorescence of the firefly. It is used to transfer information between partners. The light phenomenon produced by animals such as fireflies is called "biofluorescence." In addition to fireflies, animals such as squid and jellyfish also emit bioluminescence.

People also use fluorescence to check for leaks in pipelines. Fluorescent agent is added to the tracer, and the tracer is added to the fluid system in a certain proportion. Run the system for more than 20 minutes, illuminate the outside of the system with a UV leak detection lamp, wear special glasses, and bright yellow fluorescence will appear at the leak. After the repair is completed, use the above method to recheck for leaks. The tracer remaining in the leak can be cleaned with a special cleaning agent. The leak detector needs to be used with the tracer.

Highlighter is easy to use and interesting, but highlighter contains a lot of fluorescent agents, long-term use will cause damage to our eyesight. In addition, some fluorescent agents and fragrances added to the highlighter are toxic and harmful to the human body when used for a long time. Therefore, we should not use highlighter too much. When buying, we should also buy products from regular highlighter manufacturers, and try not to buy too cheap highlighters.