physics
DOPPLER EFFECT
Interactive simulation showing how frequency shifts when a sound source moves. Visualize wavefronts, hear the pitch change, and explore supersonic speeds.
Wave Visualization
Red circles ahead = compressed waves (higher frequency). Blue circles behind = stretched waves (lower frequency).
Parameters
100 Hz
440 Hz
2000 Hz
Stationary
50 m/s
Supersonic
M = 0.14
100 m/s
343 m/s
500 m/s
← Moving away
0 m/s
Moving towards →
0.1×
1.0×
2×
Calculated Values
Frequency (approaching)
587Hz
Frequency (receding)
329Hz
Wavelength (ahead)
0.59m
Wavelength (behind)
1.04m
How It Works
The Doppler Effect is the change in frequency (and wavelength) of a wave as a source moves relative to an observer. When the source approaches, waves are compressed, raising the frequency. When it recedes, waves are stretched, lowering the frequency.
f' = f₀ × (v + vo) / (v − vs)
Key Parameters:
• f₀ = source frequency
• v = wave speed (e.g., 343 m/s for sound in air)
• vs = source velocity (positive = away from observer)
• vo = observer velocity (positive = toward source)
• f' = observed frequency
• Mach number = vs / v (supersonic when M > 1)
• v = wave speed (e.g., 343 m/s for sound in air)
• vs = source velocity (positive = away from observer)
• vo = observer velocity (positive = toward source)
• f' = observed frequency
• Mach number = vs / v (supersonic when M > 1)
Sonic Boom: When the source travels faster than the wave speed, it creates a Mach cone shock wave. The half-angle is arcsin(v/vs) = arcsin(1/M).