Einstein got his Nobel Prize for explaining the photoelectric effect. A metal surface releases photoelectrons when it absorbs light. Einstein showed that the energy of the electrons depended not upon the brightness of the light, but upon its wavelength. In and of itself, that’s an interesting if not so exciting fact. But Einstein’s discovery implies that the world consists of tiny, discrete particles that can only have specific amounts of energy — the foundation of quantum mechanics. The key to verifying Einstein’s interpretation is measuring kinetic energy by applying stopping voltages. You can make that very measurement.

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Originally published at eHow, AUG 2011