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Physics

Excited State

Quick fact

When an electron in an atom drops from an excited state to the ground state, it can emit a photon of light with a precise color—this is why different elements produce different flame colors in fireworks.

Why this is interesting

You've seen a neon sign glow or a glow-in-the-dark toy shine—but have you ever wondered why they emit light long after being charged? The answer lies in a temporary, high-energy state of matter called an excited state.