The noble gases are
unreactive or inert, which makes them safe to use. They also glow when a
current is passed through them at low pressure. These properties lead to
many uses:
- Helium is used to fill balloons and airships, because it is much lighter than air – and will not catch fire.
- Argon is used to provide an inert atmosphere. For example it is used: as filler in tungsten light bulbs and to protect metals that are being welded.
- Neon is used in advertising signs. It glows red, but the colour can be changed by mixing it with other gases.
- Krypton is used in lasers – for example for eye surgery – and in car headlamps.
- Xenon gives a light like bright daylight, but with a blue tinge. It is used in lighthouse lamps, lights for hospital operating rooms, and car headlamps.