Ultra-Violet light is made by special lamps, for example, on sun beds. It is also given off by the Sun in large quantities. We call it "UV" for short.

Uses for UV light include getting a sun tan, detecting forged bank notes in shops, and hardening some types of dental filling.

You also see UV lamps in discos, where they make your clothes glow. This happens because substances in washing powder "fluoresce" when UV light strikes them.
When you mark your posessions with a security marker pen, the ink is invisible unless you shine a UV lamp at it.

Ultraviolet rays can be used to kill microbes. Hospitals use UV lamps to sterilise surgical equipment and the air in operating theatres. Food and drug companies also use UV lamps to sterilise their products

Suitable doses of Ultraviolet rays cause the body to produce vitamin D, and this is used by doctors to treat vitamin D deficiency and some skin disorders.

Large doses of UV can damage the retinas in your eyes, so it's important to check that your sunglasses will block UV light. The cheaper sunglasses tend not to protect you against UV, and this can be really dangerous. When you wear sunglasses the pupils of your eye get bigger, because less light reaches them. This means that if your sunglasses don't block UV, you'll actually get more ultra-violet light on your retinas than if you didn't wear them.

Large doses of UV cause sunburn and even skin cancer. Fortunately, the ozone layer in the Earth's atmosphere screens us from most of the UV given off by the Sun. Think of a sun tan as a radiation burn!