Are there really infinite colours? I have been thinking about this for some time now (well, 2 hours), and I'm still not sure. The boundaries of wavelength for the spectrum of visible light are 380 nm and 750 nm (nanometres). Now, you can get lots of different colours because fractional wavelengths are possible -- but does that mean there are infinite? If there *were* an infinite number of colours, that would surely mean that the wavelength of a wave could get increasingly and increasingly smaller. This yields the question... is there a limit on the smallest possible wavelength? If I remember correctly, the amplitude of a wave is caused by particles moving from the equilibrium line, right? So does that mean that a wavelength, of, say, 380.000000000000000000000001 nm is possible? Wouldn't this cause an attraction or repulsion between the particles? If this WERE the case, how many different wavelengths are there, and, if this question is answered, how many possible colours are there?