The noble gas used in neon signs is neon itself. Neon is a colorless, odorless gas that emits a distinct bright red-orange glow when an electric current passes through it. This property makes it ideal for use in neon lights and signs. When placed in glass tubes, the excited neon atoms produce light as electricity energizes them. Neon signs have become popular for advertising and decorative purposes due to their vibrant colors and ability to capture attention. Although neon is the most recognized gas in this context, other gases can create different colors when used in similar signs.