Time Frames for Negative Information. Late payments are black marks that normally stay on a credit report for 7 years. That's true of most negative information like foreclosures, Chapter 13 bankruptcies, charge-offs and paid tax liens; a Chapter 7 bankruptcy stays around for 10 years and unpaid tax liens can linger indefinitely.
Wiktionary (0.00 / 0 votes) Rate this definition: Doppler effect (Noun). The apparent change in frequency or wavelength of a wave that is perceived by an observer moving relative to the source of the waves. Origin: From Johann Christian Andreas Doppler, the scientist who first proposed this effect.
Doppler effect of sound waves. I am looking for interesting ways to introduce the Doppler effect to students. I want some situations in nature or every day life, where a student is possibly surprised and may ask how could it be? The common example for Doppler effect of sound waves is the siren of a moving emergency vehicle. Clearly the siren example is one way to introduce it starting from a phenomenon. However are there other interesting, perhaps astonishing phenomena in nature or in every day life which can explained by Doppler effect of sound waves?