You can use a photodiode connected to speakers to hear clicks when a photon is detected. But when I said “mere act” I just meant that it was strange that something that is easily done such as observing and detecting the photons could completely collapse the wave function.
How exactly does the mere act of observing collapse the wave function of, say, photons? I don't quite understand that one. And Richard Feynman's question related to Young's double slit experiment and the fact the electron went through both slits, as well as neither, and just one slit, and just...