While some suspended material will be large enough and heavy enough to settle rapidly to the bottom of the container if a liquid sample is left to stand ( the settable solids ) , very small particles will settle only very slowly or not at all if the sample is regularly agitated or the particles are colloidal .
Some suspended material will be large enough and heavy enough to settle rapidly to the bottom if a liquid sample is left to stand . Very small particles settle very slowly or not at all if the sample is regularly agitated or the particles are colloidal .