Not all rain is the same. The droplet size can vary considerably - in a fine drizzle the droplets are tiny, in a thundershower they are significantly larger. Max von Wolff has developed an apparatus with which the droplet size can be precisely measured. It won him the national prize in the physics category. The principle behind his development: the raindrops fall onto a plastic membrane, causing it to vibrate. Sensitive sensors record this fine tremor and transmit the measured values to a computer, which classifies the drops according to their size. In this way, the young researcher can determine whether small or predominantly large drops are falling from the sky during a rainstorm - relevant basic information for better predicting the course of a hurricane, for example.