Light
The Physics:
You’ve probably heard of fluorescent lights. Well, now you know what makes them light. The bulb contains a gas that emits ultra-violet (UV) light when it is turned on. That UV light makes the coating on the glass glow. And, if you’ve seen the inside of a tanning booth, you’ll probably notice that those bulbs they use, look a lot like fluorescent light bulbs. Well, they are, they just use a different type of glass – one that lets the UV light through.
Sometimes called Black Light, ultra-violet light makes things glow, It's called fluorescence.
![Colorful Slinky in White Light](https://wonders.physics.wisc.edu/wp-content/uploads/sites/219/2017/05/White_Light_slinky.jpg)
![Colorful slinky in ultra violet light](https://wonders.physics.wisc.edu/wp-content/uploads/sites/219/2017/05/UV_Slinky.jpg)
Have you heard of laundry detergents that make your clothes "white and bright"? Well, they put stuff in the detergent that glows under ultra-violet light.
![Detergent in White Light](https://wonders.physics.wisc.edu/wp-content/uploads/sites/219/2017/05/Detergent_White.jpg)
![Detergent in ultra violet light](https://wonders.physics.wisc.edu/wp-content/uploads/sites/219/2017/05/Detergent_UV.jpg)
Other Examples of Ultra-Violet Light
![Some rocks glow under UV light](https://wonders.physics.wisc.edu/wp-content/uploads/sites/219/2017/05/Rocks.jpg)
![Teeth glow, and so do Roger's contact lenses](https://wonders.physics.wisc.edu/wp-content/uploads/sites/219/2017/05/Teeth.jpg)