I understand why increasing the temperature of a fluid would increase its entropy, as the particles are free to move, and therefore an increase in kinetic energy would allow the particles to move more, thus increasing the fluid's entropy.
However, this doesn't make sense to me in the case of a solid - increasing the solid's temperature would result in an increase in K.E., but this would only result in the particles vibrating more. As entropy is defined as the 'disorderliness' of a system, and the molecules in a solid always remain in the same 'order' regardless of temperature, how is temperature proportional to entropy in a solid?