1. Electrons Get Excited

* Electric Current: A high voltage electrical current is passed through the glass tube containing neon gas. This current creates a flow of electrons within the tube.

* Collision: The electrons collide with neon atoms. This collision imparts energy to the neon atoms, moving their electrons to higher energy levels (excited states).

2. Atoms Relax and Emit Light

* Unstable Excited State: The excited state of the neon atom is unstable.

* Energy Release: The excited electrons quickly return to their ground state (lower energy levels), releasing the excess energy as photons of light.

* Color: The specific color of the light emitted depends on the energy difference between the excited and ground states of the neon atom. For neon, this energy difference corresponds to a reddish-orange color.

3. The Importance of Low Pressure

* Collision Frequency: Neon signs operate at low gas pressure. This ensures that there are fewer collisions between neon atoms and electrons.

* Efficient Emission: With fewer collisions, the electrons have a higher probability of transferring energy to the neon atoms, leading to more efficient light emission.

4. Beyond Neon

While neon is the most well-known gas used in signs, other noble gases like argon, krypton, and xenon can also be used to create different colors. These gases have different energy levels, resulting in different wavelengths of light emitted.

In summary:

Neon signs work by exciting neon atoms with an electrical current. These excited atoms release energy as photons of light when their electrons return to their ground state. The color of the light is determined by the specific energy differences within the neon atom.