The Doppler Effect: Mysterious wavelengths


Zzzzzzzzzzp! Flash! There you go! A spiteful and cowardly camouflaged radar trap has lashed out at you once again, and another costly and questionably handsome snapshot is on its way into your post box. Fuming traffic offenders are said to have clandestinely returned to the place of crime to take revenge – fortified by a bunch of best-friends’ hercules’s and in order to punish the wicked contraption out of its wits. Ignoring, that there’s sure to be another invincible clone around the next corner. Instead of adding up on the offence front, avoiding speeding and/or respecting red traffic lights may actually do the trick fairly well and entail far less trouble: It allows short tempers to lie dormant just a little longer and lends bank statements a so much more encouraging appearance. Similar to police records …

None of the above is poor Christian Doppler’s responsibility, though. His initial invention had nothing to do with measuring the frequency of radio waves caused by speeding drivers. When the Austrian mathematician and physician contrived the so-called Doppler Effect back in the mid 19th century, Carl Benz had not even developed his gasolene engine yet. The first „car“ ever rumbled upon German streets on New Year’s Eve of 1879, 26 years after Doppler’s death. Albeit: Each and every one of us is exposed to the Doppler Effect in our daily lives without most of us realising it: sirens screaming from ambulance and fire brigade vehicles are the most common examples.

„The Doppler effect is the change in frequency of a wave for an observer moving relative to its source.“ Doesn’t help? Still all Greek? Watch this Youtube video, which delivers at least part of the solution. Header image: This file is ineligible for copyright and therefore in the public domain because it consists entirely of information that is common property and contains no original authorship.