In 1887, Heinrich Hertz[23]: 843–44 [24] discovered that electrodes illuminated with ultraviolet light create electric sparks more easily. In 1905, Albert Einstein published a paper that explained experimental data from the photoelectric effect as being the result of light energy being carried in discrete quantized packets, energising electrons. This discovery led to the quantum revolution. Einstein was awarded the Nobel Prize in Physics in 1921 for "his discovery of the law of the photoelectric effect".[25] The photoelectric effect is also employed in photocells such as can be found in solar panels. 135 years so far.