Hi. I've just started learning about quantum mechanics, and I find the whole subject very interesting. I have read about the double-slit experiment, and I didn't understand a couple of things. Assuming one were to fire one particle at a time at the diffraction slit: - will all particles pass through the double-slit thingy, or will some remain on that board without passing through the slits? - I understand electromagnetic waves do not really carry energy, but merely determine where the particle will land. Is that correct? - Photons travel at the speed of light, right? So would it be possible to determine the trajectory of a photon by calculating the time that passes between emission and reception? So that you would know which slit it passed through? - Do the aforementioned waves travel at the speed of light as well? If so, how does it make sense that they can interfere with each other, when they fall on the screen at different times? - If the waves and the photons travel at the speed of light, and if you can determine the time between emission and reception, then some photons should be determined to have passed through the nearest slit to the point where they 'land'. But in order for particles to determine where they land, they should need information from the diffracted waves from both slits, yet the wave from the slit farther away shouldn't even have reached the reception screen by that time. How can this be explained?