Video narration
If you make light brighter, shouldn't it eventually knock electrons out of metal? Sunlight warming your skin shows light transferring energy to matter, but warming isn't the same as freeing an electron from metal. The photoelectric effect is this release: light hits metal and electrons escape. Light arrives in tiny packets called photons, and each photon must carry enough energy for an electron to break free. Here's the catch: brighter light sends more photons, not stronger ones. Frequency sets each photon's energy. So brightness can mean more emitted electrons from the surface, but only above that metal's threshold. Below it, even intense light cannot free electrons. Above it, higher frequency raises the maximum energy of escaping electrons. That threshold depends on the metal. So no: brightness alone won't do it. Each photon must meet the metal's threshold frequency.