Neon signs work by creating light through the excitation and de-excitation of neon atoms within a glass tube.
How Neon Signs Create Light
Neon signs create light through a process involving electricity and neon gas. When high voltage electricity is passed through a tube filled with neon gas, the following steps occur:
1. Ionization of Neon Gas
- A high voltage is applied across a glass tube filled with neon gas.
- This high voltage is sufficient to strip electrons from some of the neon atoms.
- When an atom loses electrons, it becomes positively charged and is known as an ion.
- This process turns the neon gas into a mixture of positively charged ions and free electrons.
2. Excitation and Collision
- The freed electrons are accelerated by the electric field.
- As the neon atoms, ions and electrons bounce around the tube, they collide with each other, gradually increasing in energy.
- These collisions transfer energy to the neon atoms.
- The energy from these collisions excites the electrons in the neon atoms.
- Excited means the electrons jump to a higher energy level.
3. De-excitation and Light Emission
- The excited state is unstable, so the electrons eventually return to their original, lower energy level.
- When the ionised atoms recapture their electrons to become neutral again, they release a particle of light known as a photon, which is what causes neon to give off a bright, coloured glow.
Summary Table
| Step | Description |
|---|---|
| Ionization | High voltage strips electrons from neon atoms, creating ions and free electrons. |
| Excitation | Collisions between ions, atoms, and electrons transfer energy, exciting the electrons in neon atoms to higher energy levels. |
| De-excitation | Electrons return to their original energy levels. |
| Light Emission | Energy is released as photons (light). |
