Does wavelength change for a moving observer ?

Relative scientists claim that it does not change and that is why my demonstration of light speed invariance in classical phyiscs is wrong.

Here is what ChatGPT/Copilot says:

Does the observed wavelength change for a moving observer ?

Yes — the observed wavelength does change for a moving observer. This is the essence of the Doppler effect. Let’s break it down carefully:

🚦 Classical (Sound Waves in a Medium)

• If the observer moves toward the source, the waves are encountered more frequently → shorter observed wavelength and higher frequency.

• If the observer moves away from the source, the waves are encountered less frequently → longer observed wavelength and lower frequency.

• Formula (for sound in a medium with speed $v$):

$$f^{\mathrm{\prime }}=f\cdot \frac{v\pm v_o}{v}$$

where:

• $f^{\mathrm{\prime }}$ = observed frequency

• $f$ = source frequency

• $v$ = wave speed in medium

• $v_o$ = observer speed (positive if moving toward source)

Since wavelength is $\lambda =v\mathrm{/}f$, the observed wavelength changes accordingly.

https://copilot.microsoft.com/shares/GarLXebCqmAULmbvLSZZ3

So my demonstration stands.