Doppler Effect

                                                   Doppler effect Close your eyes and listen.  Can you hear the exact moment the waves switch from  The Squeeze  to  The Stretch? Have you ever wondered why a siren sounds high-pitched as it rushes toward you, but drops to a lower sound the moment it passes? That is the Doppler Effect ! what is Doppler effect? The Doppler Effect is the change in frequency of a wave as the source and observer move relative to each other. When approaching, waves compress and frequency increases. When receding, waves stretch and frequency decreases. How it Works: Sound travels in waves. When a moving object makes noise, it changes how those waves reach your ears: Compression (The Squeeze): As a car moves toward you, its squishes the sound waves together. These waves hit your ear more frequently (high frequenc...