Neon glows because of a process called gas discharge, where electricity excites neon atoms, causing them to emit light.
Here's a more detailed explanation:
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The Setup: Neon lights are glass tubes filled with neon gas at low pressure. There's a metal electrode at each end of the tube.
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Ionization: A high voltage (several thousand volts) is applied to these electrodes. This strong electric field rips electrons from the neon atoms. This process is called ionization, and it creates a plasma – a mixture of positively charged neon ions and free electrons.
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Excitation: These free electrons, accelerated by the electric field, collide with other neon atoms. When an electron hits a neon atom, it can transfer energy to the atom, bumping one of the atom's electrons to a higher energy level. This is called excitation.
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Emission of Light: The excited electron is unstable in this higher energy level and quickly falls back to its original, lower energy level. When it does, it releases the extra energy in the form of a photon of light.
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Characteristic Color: The energy difference between the higher and lower energy levels in neon atoms corresponds to photons of red-orange light. This is why pure neon glows with a distinctive red-orange color.
Different gases, or mixtures of gases, will glow with different colors because their atoms have different energy levels and release photons with different energies (and therefore, different colors). While the name is "neon" lighting, many "neon" signs don't actually use pure neon.
In summary, neon glows due to the excitation and subsequent de-excitation of neon atoms caused by electrical discharge, releasing photons of light in the red-orange spectrum.
