>What exactly does it mean that light moves as a wave or a particle?
One idea is known as the Copenhagen interpretation.
It basically says that the wave-like effects we associate with matter is merely a wave of probabilities. Or in terms of the double-slit experiment and in other words, light behaves like a particle, but the wave-like effects you see is just the result of probabilities where the particles end up. Dark areas are areas of low probability, and lighter areas high probability.
One might imagine the light particles streaming through the slit end up having slight variation in trajectory from one particle to another (for various reasons such as interference with other particles), which results in areas where most particles end up and others where few end up... representing a wave.
One idea is known as the Copenhagen interpretation.
It basically says that the wave-like effects we associate with matter is merely a wave of probabilities. Or in terms of the double-slit experiment and in other words, light behaves like a particle, but the wave-like effects you see is just the result of probabilities where the particles end up. Dark areas are areas of low probability, and lighter areas high probability.
One might imagine the light particles streaming through the slit end up having slight variation in trajectory from one particle to another (for various reasons such as interference with other particles), which results in areas where most particles end up and others where few end up... representing a wave.